Visual Reference
Key Diagrams
Right Triangle — Pythagorean Theorem
Circle — Radius, Diameter, Arc
Area Formulas — Common Shapes
Reference
Core Formulas
Pythagorean Theorem
a² + b² = c²
For any right triangle: the sum of squares of legs equals the square of the hypotenuse.
Circle Area & Circumference
A = πr² · C = 2πr
r = radius. Diameter d = 2r. π ≈ 3.14159.
Triangle Area
A = ½ · b · h
Base times perpendicular height, halved. Works for any triangle.
Rectangle & Square
A = l · w · P = 2(l+w)
Area = length × width. Square: A = s² since l = w = s.
Sphere Volume & Surface
V = ⁴⁄₃πr³ · SA = 4πr²
Both formulas use the radius r of the sphere.
Interior Angles (Polygon)
Sum = (n−2) · 180°
n = number of sides. Triangle: 180°. Quadrilateral: 360°.
Practice
Test Your Knowledge