Have a look at this example question, then try the question below. A cable is attached, 30 metres above ground level, to a post. The other end of the cable is 14 metres from the base of the post.

If the sides of the right-angled triangle are labelled 𝑎, 𝑏 and 𝑐 then Pythagoras' theorem can be written as the formula 𝑎² + 𝑏² = 𝑐². Pythagoras' theorem can be used to find the length of line ...