Foundation & Higher

Pythagoras GCSE questions

Pythagoras questions GCSE: find a missing side in a right-angled triangle. a² + b² = c², where c is the hypotenuse.

Which side?

The hypotenuse is opposite the right angle and is the longest side. If you are finding a shorter side, subtract after squaring.

Practice questions

Cover the answers and have a go first. Worked solutions are underneath.

Question 1 [2 marks]

Legs 3 and 4. Hypotenuse?

Question 2 [2 marks]

Legs 5 and 12. Hypotenuse?

Question 3 [2 marks]

Hypotenuse 10, one leg 6. Other leg?

Question 4 [2 marks]

Is a triangle with sides 6, 8, 11 right-angled?

Question 5 [3 marks]

A 9 m ladder reaches 8 m up a wall. How far is the base from the wall? 1 d.p.

Common mistakes

Answers and working

Q1. 5
Q2. 13
Q3. 8
Q4. No: 36 + 64 = 100 ≠ 121
Q5. √(81 − 64) = √17 ≈ 4.1 m

Frequently asked questions

Full method?

See the Pythagoras lesson for labelled diagrams and 3-4-5 triples.

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