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8
votes
1answer
23 views

How to prove that it is possible to make rhombuses with any number of interior points?

I was given some square dot paper which can be found on this link: http://lrt.ednet.ns.ca/PD/BLM/pdf_files/dot_paper/sq_dot_1cm.pdf and was told to draw a few rhombuses with the vertices on the dots ...
2
votes
1answer
22 views

A “house” (pentagon) with square height $x$ and triangle height $\frac12x$…

Imagine a simple drawing of a "house," a triangle with half of the height of a square that it's laying on, to form a pentagon. If the square's height is $x$ and the triangle's height is $\frac12x$ ...
-3
votes
0answers
22 views

How to define shapes [duplicate]

What sort of orientated shapes are defined in an XY grid with exactly three nontrivial expressions, when those expressions can be solved with two unknowns. I think that the golden rectangle is an ...
0
votes
1answer
33 views

Definition of the golden rectangle? [duplicate]

Is this true: The golden rectangle is defined as: X=A+B Y=A Y:X is as B:Y For bonus points: what other shapes with defined orientation but undefined size can be defined in an XY grid by using ...
0
votes
0answers
17 views

Does this construction method produce all possible convex pentagons (up to similarity)?

I read a question somewhere here about convex pentagons. I began to wonder if there was a way to list all possible convex pentagons and came up with the following method: 1) Draw a base line AB of ...
0
votes
0answers
33 views

Constructing a pentagon from a circle

To my understanding you can create any regular N sided shape by using a circle. I decided to give this an attempt from the equations/ formulas given from the internet. Just a side note - is it ...
0
votes
0answers
13 views

What width of material will give the least waste when cutting 3 different sized shapes from it?

I have a finished product that is made from 3 parts. The size of each of the 3 parts that make the finished product are as follows: Ellipse 83cm x 67cm Rectangle 235cm x 5cm Rectangle 130cm x 5cm ...
0
votes
0answers
23 views

Finding the vertices of a square giving the mid point and radius

I'm a programmer with terrible mathematics skills, but I'm getting by with studies. I'm trying to find out the vertices (x,y) of a square, giving the ...
0
votes
0answers
28 views

Non-existent polygon.

Every website I go to which lists all 2-Dimensional polygons begins from the three-sided triangle and works up from there. Given that the area of any regular polygon can be calculated (in degrees) ...
0
votes
0answers
19 views

Can this set of points be called a geometric shape?

If I have a graph $G = (V, E): V \subset R^2, E \subset (R^2, R^2)$, can its visual representation be called a geometric shape if it has edges that are fully enclosed within the minimum area hull of ...
0
votes
1answer
75 views

How's it possible that for two or more shapes given the same area, that each shape can have distinct perimeters?

I've just 'discovered' (of course am not the first though) a very strange property in geometry relating to the the relationship between the Area and the Perimeter of an object. Say you have box A ...
0
votes
1answer
82 views

volume of water in the the pool and domain range of function question

im working on advanced problems and the question is following: A swimming pool is 20 ft wide, 40 ft long and 3 ft deep at the shallow end, and 9ft deep at its deepest point. 1) Express the volume of ...
1
vote
1answer
70 views

Super conic sections?

I know graphs of the form $A x^2 + B xy + C y^2 + D x + E y + F = 0$ are conic sections. But what would happen if I changed the highest power to 3? Would this be a new 3D shape, a 4D version of it, or ...
1
vote
1answer
30 views

Can a 1-side, 1-border object exist in 3D?

We are three friends discussing whether a three dimensional object with a single side and a single are can possibly exist. I first came up with a Moebius strip as an affirmative example The second ...
-1
votes
1answer
68 views

Why are circles always 360 degrees? [duplicate]

Please Answer quickly i am really confused Most websites say that people thought a circle is 360 degrees because there are 360 dayes in a year but there are not they also say that the base number is ...
0
votes
1answer
94 views

Area of ellipse formed by slicing a cylinder

What is the equation of the area of the ellipse when a cylinder of radius x is cut by a plane inclined at an angle a. Angle a is the angle between the plane and the axis of the cylinder. If a is 90 ...
1
vote
2answers
73 views

How to get proficient?

I'm currently a 1st year undergrad and I feel like my mathematical ability is very poor. I want to get better at a lot of different areas so I can feel very comfortable with mathematics. I see ...
60
votes
10answers
11k views

Is there a shape with infinite area but finite perimeter?

Is this really possible? Is there any other example of this other than the Koch Snowflake? If so can you prove that example to be true?
0
votes
1answer
104 views

Use of Delaunay Triangulation and Voronoi Diagram to find alpha shape using Edelsbrunner's algorithm

I am learning how to find the shape of a set of points in 2-D. I understand that Alpha Shape method is a good way to find the shape of a set of points. Alpha Shape was originally introduced by H. ...
0
votes
2answers
58 views

Question on volume of swimming pool

Swimming pool is of length 20m, wide 5m and height of the swimming pool increase from the 1.6m to 4.4m. What is the volume of swimming pool? How I approached: Area of swimming pool = Area of cube + ...
1
vote
2answers
96 views

cube / shape question for my daughter (which I can't answer)

5cm sided cube. If a 1cm cube is cut from each corner, how many faces will the new shape have? Thank you
1
vote
0answers
32 views

unique cube arrangments

i have received this math riddle which i cannot solve, the riddle: given a set of cubes, a unique shape is any shape that was created joining cubes sides together and does not match any previously ...
1
vote
2answers
62 views

Oval/quadrupole characterization

Context: Points on a circle satisfy the equation: $$x^2+y^2=r^2$$ where $r$ is the radius. In a similar manner one can show for an ellipse: $$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$$ is satisfied($a$ ...
1
vote
1answer
162 views

Finding the radius and height of a cone inside a cone

I need to find the volume of a metal cone that is hollow with a thickness of 2cm. The radius of the big cone is 8cm and the height is 12. The thickness determents the radius, and height of the little ...
1
vote
0answers
13 views

create polygon section with equal sides

I have to create essentially these sections of a polygon. I have width(W) and height (H), and number of sides (3 on left abc and 4 on right image ABCD) I need each side to be equal. How can I ...
0
votes
2answers
37 views

How to define distance between two functions in a non-linear space (example of non-linear space: shape space)?

Suppose I have two parametric circle $f_1=(acost,asint)$ and $f_2=(bcos t,bsint)$, $t\in(0,2\pi),a>0,b>0$, which lies in some non-linear space. Are there any way, how to define the ...
0
votes
2answers
22 views

Rectangular Bisection

This may be a really stupid question but... If I bisect a rectangle twice diagonally. Do all the angles at the corners equal 45°? So, if I drew this diagram accurately, would each red angle equal ...
2
votes
1answer
45 views

Do two lines lay in the same 4-dimensional plane

I don't know how quite to phrase this, but I'll try. Because two point are co-linear and two lines cannot always be used to define a plane and aren't always in the same plane, are two lines always ...
1
vote
2answers
39 views

Isosceles Trapezoid Diagonal Lengths

In isosceles trapezoid $ABCD$, $AB=6$, $BC=9$, $CD=8$, and $AD=9$ find the distance from point $D$ to $BC$ (perpendicular).
0
votes
1answer
95 views

What is “Disjoint line segments”?

I'm unable to find a definition for disjoint line segments. Can someone please define it and if possible show images with examples?
0
votes
0answers
34 views

Recognize a shape with a set of Data points

So I have a number of points on graph. For Ex: (1,1) (2,5) ......... and so on. And I want to recognize which shape is it closest to from circle, triangle and rectangle. -By closest I mean ...
1
vote
2answers
56 views

Name for shape defined by volume between two concentric spheres

Is there a proper name for a shape defined by the volume between two concentric spheres? My understanding is that, formally, a "sphere" is strictly a 2D surface and there's a formal term for volume ...
3
votes
1answer
246 views

Can we rotate a 3D lattice of deformed spheres?

EDIT by EricStucky: The full text of original post below for reference, but I have talked with the OP in chat and believe that this is the mathematical core of the question. Suppose that we have ...
3
votes
1answer
204 views

Prove that there is only one way to make a square using all six tangram pieces

I am pretty sure there is only one way to make a square from the six tangram pieces: How can I prove this is the only way respecting all symmetries?
6
votes
1answer
87 views

Name of a shape that is intersected once by each ray that starts at a given point

Is there a particular name for a shape that is intersected exactly once by each ray that starts at a given point? To illustrate: I'm looking for a name for shapes like the left one in this image: ...
1
vote
0answers
32 views

Geometric figures inside a bounding box

Let us suppose that we have a bounding box of length $l$, width $w$, and breadth $b$. I wish to know the dimensions / characteristics of a tetrahedron cylinder cube pyramid inside this bounding ...
0
votes
1answer
33 views

Inverting complicated function (possibly using secant root finder)

So I have the following equation from the 2002 paper "A Rapid Hierarchical Rendering Technique for Translucent Materials" http://graphics.ucsd.edu/~henrik/papers/fast_bssrdf/fast_bssrdf.pdf Here is ...
-1
votes
1answer
554 views

Cut A Shape Into Two Triangles

I have this shape: , and I want to put a straight line somewhere through the shape to cut it into two triangles. I know that this is possible, but I don't know how. Any help is appreciated!
0
votes
3answers
61 views

$x^2 + y^2 - y = 0$ is… a cylinder?

I've this question: Find the area of the intersection between the sphere $x^2 + y^2 + z^2 = 1$ and the cylinder $x^2 + y^2 - y = 0$. Is this second equation even a closed shape? If one were to ...
0
votes
1answer
145 views

Points $S$ and $T$ are on side $\overline{CD}$ of rectangle $ABCD$ such $ \overline{AS}$ and $\overline{AT}$

Points $S$ and $T$ are on side $\overline{CD}$ of rectangle $ABCD$ such $\overline{AS}$ and $\overline{AT}$ trisects $\angle DAB$. If $CT = 3$ and $DS = 6$, then what is the area of $ABCD$? I have ...
0
votes
0answers
13 views

Does the dimension of R have anything to do with proportion of inscribed triangles to their paralellepipeds?

I had a hard time deciding on how to title this question. I hope it gives people some idea so they can give me their two cents. We all know that the formula for a triangle is $$ (1/2)b*h$$ In ...
1
vote
0answers
39 views

Retanguloids and volumes

I am currently going back through all the "Challenge" questions in preparation for exams, and have come across this, any hints on how to approach?
0
votes
1answer
151 views

How do one calculate the area (m^2) of freeform shapes?

Ok, ill be honest, i'm building a patio, and for that i'd like to estimate the cost using sqm. However the shape of the patio is what you might call non-standard. So far i've been able to use ...
1
vote
2answers
163 views

Comparing the shape of two probability distributions

How do we compare the two probability distributions based on their means and standard deviations ? suppose we have the following. 1st probability distribution mean = 0.6645 SD = 0.02345 2nd ...
0
votes
1answer
38 views

How to decide on the shape of the Beta distribution?

Suppose we toss a coin which is not fair. and the probability of success is 0.7. Is that enough to decide on the shape of it beta distribution ? what would be its shape then ? As far as I know, it's ...
0
votes
1answer
77 views

Interpolating Z-Values when given complete and incomplete XYZ pairs

I am building an application that works with PolyLineZ (ESRI Shapefile) data and rewrites outlying Z values. The minimum and maximum Z-values are defined by the user through the interface Let's take ...
0
votes
1answer
175 views

How to calculate the points of the triangles making up an Octahedron?

Ok guys, I'm not a great mathematician but will try to work this as accurately as I can. I hope someone can help me. I am drawing some 3D objects and I am having trouble drawing an Octahedron. I ...
0
votes
0answers
94 views

Estimating the geometric shape of a point cloud without using the vertex information

Consider a point cloud format that describes 3D point clouds by vertices, triangle labels and normal vectors. If we miss the vertex information, is it possible to retrieve the lost data by triangle ...
2
votes
2answers
375 views

fill a rectangle with hexagons

Suppose I have a rectangle and I want to fill it with hexagons without having any white space. The hexagon doesn't need to be in the regular hexagon shape so the only thing that matters is that it ...
4
votes
1answer
154 views

How can I understand is the picture $2D$ or $3D$

I can not understand is this picture 2D or 3D .what is the rule or condition to be a 2D or 3D picture.How can I understand that?please help me?