Geometry Basics

Essential geometry formulas and concepts for middle school

Area Formulas

Rectangle: A = length × width
Triangle: A = (base × height) / 2
Circle: A = π × radius²

Perimeter and Circumference

Rectangle: P = 2(length + width)
Circle: C = 2 × π × radius

Volume Formulas

Rectangular Prism: V = length × width × height
Cylinder: V = π × radius² × height
Sphere: V = (4/3) × π × radius³

Pythagorean Theorem

a² + b² = c²

For right triangles only. c is always the hypotenuse (longest side).

Back to Home