# Questions tagged [angle]

An object formed by two rays joining at a common point, or a measure of rotation. In the latter form, it is commonly in degrees or radians. Please do not use this tag just because an angle is involved in the question/attempt; use it for questions where the main concern is about angles. This tag can also be used alongside (geometry).

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### How Can I Calculate Irregular Polygon's Internal Angle? [closed]

For example there is irregular polygon and I choose a vertex and I want to calculate it's interior angle, the angle can be more than, less than or equal 180 degrees. How can I calculate and how can I ...
1 vote
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### Sum of "angles" of a 3D tetrahedron

We know that the sum of angles of a triangle equals the straight angle (180 degrees). Can we convert a 2D theorem to 3D? e. g. We can generalize the triangle to a tetrahedron, angles of the triangle ...
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### solve for the unknown in each triangle given and round it to the nearest tenth using the law of simes [closed]

this is the triangle one and two. find the missing or unknown in each triangle so that the triangle will be completed
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### Finding angle in circle to produce equal areas

I have a circle that is divided into 4 quadrants with a vertical and a horizontal axis. The center of the circle (where the axes cross) is point b. The top of the vertical axis is point d. On the ...
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### Calculating the angle between 2 one-sided surfaces.

For a piece of software that I am writing, I need to determine the angle between two 3-dimensional one-sided surfaces that intersect at a line. The surfaces are defined as triangles with a normal ...
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### MSE of the Phase Estimation of a Noisy Complex Quantity

Presentation of the Problem I am making a measurement which yields me the complex quantity: S_k = e^{i \cdot \phi} + X_k + i \cdot Y_k \quad \text{with} \quad X_k, Y_k \stackrel{iid}{...
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### Calculate Intersection point of 2 Lines with angle [closed]

I would like to calculate an intersection point of two lines in a 2D area. I think it should be really simple but i cannot figure it out. I have two points P1(x,y), P2(x,y) and 2 angles alpha and beta....
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### Solving angle relationships in triangles with limited information

What is the relationship between angles $\angle abd$ and $\angle acd$, when line $bc=\frac{1}{2}$ and line $ac=30$? b c and d are in a straight line, and point d is a right angle The answer should ...
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### Locus of a trajectory [closed]

If a stone is thrown at an angle of elevation of 45 degrees. What would be the locus of its trajectory? How would you sketch this? Problem The answer appears to be the arc of a circle, but shouldn't ...
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I have a quadrilateral ABCD. If I know the angles $DAB, DCB, ADB, CDB, ABD, CBD$, can I obtain the angle $DAC$? I know that I can do it by some coordinate geometry or the sine formula, but is there a ...
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### Formula of an area of sector of circle without notating a radius of a circle

The following quotes are from this book(A First Course in Calculus by Serge Lang) Suppose we are given a continuous function $$r=f(\theta)\tag{1}$$ which is defined in some interval$~a\le\theta\le b~$...
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### APMO 2020 Geometry Problem | Proving lines to be concurrent

PROBLEM Let $\Gamma$ be the circumcircle of $∆ABC$. Let $D$ be a point on the side $BC$. The tangent to $\Gamma$ at $A$ intersects the parallel line to $BA$ through $D$ at point $E$. The segment $CE$ ...
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### Which coordinates go first when calculating an angle from point A to point B?

I'm trying to design a 2D game and am working on monster movement right now. I need to calculate the angle a monster moves towards when they move from location A to location B (so I know which ...
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### Angles of Triangle in Two Coordinate Systems

If I know the coordinates of three points in a known coordinate system, I can calculate the angles of a triangle that includes those three points. However, if I observe the same three points in an ...
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### Projecting 2D coordinate into 3D space with camera matrix

I am not entirely sure that this is the right place to ask or if my problem is solvable, but I am out of ideas and googling hasn't brought me any closer to a solution unfortunately. Again if anyone ...
1 vote
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### To which angle do the wheels have to turn relative to their current position in order to turn correctly toward the object?

I am trying to write an algorithm to turn the EV3 robot (https://d2nmr6p48f8xwg.cloudfront.net/content_pictures/pictures/000/001/570/814c51fb41fab7a3e3039ec6a067accc510a9341Lego-Mindstorms-Ev3-Car-...
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1 vote
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### Negative angle in radians [closed]

I compute an angle of a vector in radians and it is negative (<0, for example _ -5, -150..) I am going to use cordic to compute sin and cos. For cordic I use the full circle ( 0 - 360), positive ...
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### Why is this angle taken as negative?

Question: The resultant of two concurrent forces, $\vec{P}$ and $\vec{Q}$, $[P>Q]$, trisects the angle between them. Show that the angle between them is $3\cos^{-1}\left(\frac{P}{2Q}\right)$ and ...
• 2,207
1 vote
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### How is my book finding the magnitude of the resultant differently?

Question: Forces of magnitude $Q-R$, $Q$, $Q+R$ act at a point in directions parallel to the sides of an equilateral triangle taken in order. Find the magnitude of their resultant. My attempt: Let ...
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1 vote
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### Angle between plane and line

I'm getting a really large angle when I work out this problem and I'm not sure why. I have a plane which has the equation: $0.19x-0.68y+0.7x = -2.19$. I took a point which is on the plane and called ...
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### Distance between two objects given their angle of depression

A boat is situated between a lighthouse and a ship such that all three of them are in a straight line. If the angles of depression of the boat and the ship from the top of the lighthouse $20$ meters ...
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$ABC$ and $ADB$ are isosceles triangles. Given $\beta,$ $R$ and $h$, how can I find angle $\alpha$? $\beta$ is the top angle of the triangle $ABC$, so $\angle{ACB}$. $h$ is the change in height ...
In a $\Delta ABC$, $O$ is a point in its interior such that $OA=12$cm, $OC=9$cm and $\angle AOB=\angle AOC=\angle BOC$ and $\angle ABC=60^\circ$. Then what is the length of $OB$ (in cm)? 6√3 4√3 4√6 ...