# What are some good resources for brushing up on geometry and trigonometry?

I'm brushing up on my calculus, and geometry and trigonometry keep coming up. However, these are probably my weakest areas mathematically. Are there any good sites or free PDFs/ebooks that I can use to quickly (in a weekend, preferably) work through geometry and trigonometry and refresh myself in topics such as areas and volumes of various geometric shapes, trigonometric functions, relationships between angles of a given shape or structure?

It's been over 8 years since I took a geometric or trigonometric course (it was back in high school) and over 2 years since I took any course that even relied on geometry or trigonometry. I'm not looking for anything incredibly complex, either. Just something to cover the topics that I'm encountering in integral and differential calculus.

Hey there are lot of sources available on the internet. I enlist a few of them here.

1) http://www.free-ed.net/free-ed/Math/Trigonometry/trig02_SPK.asp This website provides an nice introduction, which is very basic in nature.

2) For geometry you can read this book by a very good Mathematician, which is available online : http://math.mit.edu/~kedlaya/geometryunbound/

I am sure gigapedia.com will have lots of ebooks on this subjects. Try searching it.

• Thanks for this gigapedia - I've never heard of it before, but it looks interesting. The other links are also good too. A problem that I've found is finding something that's not so elementary its boring, but also hits on the points that I care about. – Thomas Owens Aug 28 '10 at 0:28

Although it's a little basic, I managed to find a "geometry reference sheet" (direct PDF download). It's got your standard two- and three-dimensional shapes, plus your law of sines, law of cosines, distance, and midpoint formulas. Although if it's been years since you had to find the volume of a sphere, this kind of thing might be useful.

If you are starting trigonometry I'd suggest you to solve Plane trigonometry book by S.L. Loney

I recommend the following books:-

"Geometry" By David Hilbert and "Trigonometry" By I.M Gelfand