# Geometry

To calculate the length of a side on a right-angled when you know the sizes of the other two, you need to use Pythagoras' Theorem.

Pythagoras' Theorem says that, in a right angled triangle:

The square of the is equal to the sum of the squares on the other two sides.

We can write this more simply as :

## Calculating the length of the hypotenuse

Question

Use Pythagoras' Theorem to calculate the length of the hypotenuse. Give your answer to 2 decimal places.

Write the equation

Square the lengths you know

Find the square root

Question

Calculate the length of side

### Example

Calculate the length of the side marked .

• Write the equation:
• Organise the equation . To find the length of a short side, we can also use the formula
• Square the lengths you know:
• Do the subtraction:
• Find the square root:

Question

Calculate the length of side a.