# Free Geometry Help

Need some geometry help? We have more than thirty excellent geometry lessons here, broken up in general topics. Make sure to browse all of the topics to find what you need, or search by keyword.

## Graphing Lines

- Asymptotes
- Domain and Range
- Finding Asymptotes
- Finding Horizontal Asymptotes
- Point Slope Form
- Slope Intercept Form
- Slope of a Line
- X-Y Axis
- Graphing a Parabola

## Shapes

- Triangles
- 30-60-90 Right Triangle
- Parallelograms
- Trapezoids
- Special Parallelograms
- Congruent Triangles
- Isosceles Triangles
- Polygons

## Angles, Lines, and Points

- Distance Formula
- World of Angles
- Special Angles
- Parallel Lines
- Length of a Line Segment
- Sum of the Angles of a Triangle
- Exterior Angles of a Triangle
- Interior Angles of a Polygon
- Triangle Inequalities
- Midpoint Formula

## More Lessons

## Formulas

## Other Stuff

## Lessons from Other Sites:

- Areas, Volumes, Surface Areas
- Circumference of a Circle
- Classifying Angles
- Conic Sections/Circles
- Interior Angles of Regular Polygons
- Polygon Basics
- Pythagorean Theorem
- Three-Dimensional Figures

## Recent Geometry Questions

80 degrees *Monday January 21, 2019*

Can anyone help me see why ACB is 80 degrees?
I have tried playing with parallel lines and basic ideas of geometry and some similar triangles stuff.
Any hint

Geometry help needed by guitar builder *Sunday January 20, 2019*

Attachment 10932

trigonometry identities equation *Sunday January 20, 2019*

Hi I struggle with equation ((1+sin(2x)+cos(2x)) / (1+sin(2x)-cos(2x))) =Cot(x) tried lots of different identities for 2 houres and have no progres I had some more simple one explained on lecture

Unit Circle Trigonometry Quick Question *Sunday January 20, 2019*

This is just a simple question but I cant find the solution to this problem online and our teacher never explaines this part:
Find all possible values of the angle:

Unit Circle Trigonometry *Sunday January 20, 2019*

Let sin 20◦ = k. Express the following in terms of k.
a) sin 340
b) cos 200
c) tan 160
d) cot 70
Been trying to solve this for a while, I have a math test