# Maths - Rules - Graphs

**The equation of a straight line is:**

## y = mx + c

**The gradient, m:**

## m = Change in y-values ÷ Change in x-values

**Quadratic functions are written in the form of:**

## Y = ax² + bx + c

**Cubics are in the form:**

## Y = ax³ + bx² + cx + d

**In a pie chart, to find out the frequency that each section represents measure the angle for the section then:**