Shapes

This course is a part of Basic geometry, a 8-course Topic series from Khan Academy.

Classify shapes and solve problems using what we know of the properties of shapes.

This course contains 6 segments:

Properties of shapes

Learn how different shapes have different numbers of corners, different side lengths, and so on. Use these properties to help you recognize shapes.

Quadrilaterals

Not all things with four sides and 90 degree angles are squares or rectangles! Sometimes the angles in these 4-sided shapes are less than (or greater than) 90 degrees, causing them to have a slightly odd shape. These are called quadrilaterals and come in a few different varieties. In this tutorial, you'll learn about them.

Triangles

Triangles can be classified in different ways. In this tutorial, we'll learn about scalene, isosceles, equilateral, acute, right, and obtuse triangles.

Classifying geometric shapes

Practice classifying geometric shapes.

Triangle angles

Do the angles in a triangle always add up to the same thing? Would I ask it if they didn't? What do we know about the angles of a triangle if two of the sides are congruent (an isosceles triangle) or all three are congruent (an equilateral)? This tutorial is the place to find out. Common Core Standard: 8.G.A.5

Geometric solids (3D shapes)

Identify 3-dimensional figures and their parts (faces, edges, vertices).