# Arc Lengths Worksheets

## Arc Lengths Formula

The image below shows the formula for arc length. The symbol used to represent the angle of the sector for the arc length is known as theta Θ. Theta is a Greek letter. In the formula "r" represents the radius. In the formula the symbol π represents the irrational number pi (3.142...)

## What is Pi?

Pi is an irrational number - it cannot be written as a fraction a / b. Pi continues infinitely. Pi is the most famous number in mathematics. March 14th is international Pi Day - it is also the birthday of famous mathematician and scientist Albert Einstein.

## Pi Joke

The diameter of a circle fits around the circumference exactly pi times.

## Arc Lengths Question and Answer One

Below shows an example of how to calculate the arc length. The radius is 8 cm. The missing angle theta, Θ, is 30 degrees. The final answer is 4.19 cm.

## Arc Lengths Question and Answer Two

Example two asks for the missing angle Θ. It is given that the radius is 4.5 cm and the arc length is 2.8 cm. The final answer is Θ equals 35.65 degrees. The answer has been rounded to two decimal places.

For Angles Cazoomy Worksheets try: Angles Worksheets. For Area Cazoomy Worksheets try: Area Worksheets. For Compound Shapes Cazoomy Worksheets try: Compound Shapes Worksheets.