Study Guide

Basic Geometry Topics

Basic Shapes

This is where it all begins: basic shapes, lines, and angles.

Angles

Not to be confused with angels, angles are the pointed corners of shapes. Angles can be named...

Parallel Lines & Transversals

A transversal is a line, or line segment, that intersects two or more other lines, or line...

Polygons

A polygon is any closed figure with three or more straight sides. "Closed" means that there are...

Triangles

Triangles are three-sided polygons, but we're sure that you already knew that. The triangle is...

Quadrilaterals

Quadrilaterals are four sided shapes. The most common include squares and rectangles, but there...

Angles in a Polygon

As we discussed before, the three angles of a triangle always add up to 180°.In each...

Circles

A circle is the set of all points equal in distance from a center point. If you pinned a piece of...

Similar Figures

Similar figures are always the same shape, but not the same size. They have equal angles but not...

Congruent Figures

Congruent figures have the same shape and size, they're totally equal. Same-same. All of the...

Perimeter & Circumference

The perimeter of a shape is the distance around the outside of the figure. It's pretty simple;...

Area (Polygon, Triangle, Circle, Square)

Area is the amount of space inside a two-dimensional shape. If you think about the floor of your...

Area Formulas

Let's go over these area formulas one more time.Area of a Rectangle = Base × HeightArea of...

Area of Irregular Shapes

In real life figures are often irregular shapes - a little bit messy. Think of your messy bedroom...

3D Objects (Prisms, Cylinders, Cones, Spheres)

Three‐dimensional objects are the solid shapes you see every day, like boxes, balls, coffee...

Volume of Prisms & Cylinders

The volume of a solid is the amount of space inside the object. It's how much water fits inside a...

Volume of Pyramids & Cones

The formula for the volume of pyramids and cones tells you how much space is inside each...

Volume of Spheres

A ball is a sphere. A sphere is a 3-D shape. 3-D shapes have volume. So a ball has volume. What...

Surface Area

Surface Area of a Cone = πr2 + πrsTo find the surface area of a cone, we need to find the...

Pythagorean Theorem

A long time ago, in ancient Greece, a brilliant guy named Pythagoras discovered something...