Angle

Formed by two rays meeting at a point.

Perimeter

Distance around a shape.

Area

Space inside a shape. Examples: Rectangle: 𝐴 = 𝑙 𝑤 Triangle: 𝐴 = 1 2 𝑏 ℎ

Volume

Space inside a 3D object. Example: Box: 𝑉 = 𝑙 𝑤 ℎ

Radius

Distance from center of a circle to the edge.

Diameter

Distance across a circle through the center. 𝑑 = 2 𝑟

Circumference

Distance around a circle. 𝐶 = 2 𝜋 𝑟

Pythagorean Theorem

For right triangles: 𝑎 2 + 𝑏 2 = 𝑐 2