Pythagoras’ theorem
Answers are for parents and teachers.
1
Find the hypotenuse of a right-angled triangle with legs 15 and 20.
225 + 400 = 625, so c = 25.
2
The hypotenuse is 26 and one leg is 10. Find the other leg.
676 − 100 = 576, so the leg is 24.
3
Is a triangle with sides 9, 40 and 41 right-angled?
81 + 1600 = 1681 = 41². Yes.
4
Classify the triangle with sides 8, 10 and 12.
144 < 64 + 100 = 164, so it is acute.
5
A 6.5 m ladder has its foot 2.5 m from a wall. How high does it reach?
42.25 − 6.25 = 36, so it reaches 6 m.