Grade 8 · Pre-Algebra

Grade 8 Pre-Algebra — Pythagorean theorem questions and answers

a² + b² = c² on right triangles. Written in American English for students, parents, and teachers in the United States.

Practice quiz

Open a card to see the answer. These are original practice items for US elementary students — not a state test copy.

1. The Pythagorean theorem is

Answer: a² + b² = c²

Only for right triangles; c is the hypotenuse.

2. The hypotenuse is

Answer: the side opposite the right angle

It is the longest side.

3. If a = 3 and b = 4, c =

Answer: 5

9 + 16 = 25, √25 = 5.

4. If a = 5, b = 12, c =

Answer: 13

25 + 144 = 169, √169 = 13.

5. A 6-8-10 triangle is a

Answer: scaled 3-4-5 right triangle

Multiply 3-4-5 by 2.

6. If c = 10 and a = 6, b =

Answer: 8

36 + b² = 100 → b² = 64.

7. You can use the theorem to find

Answer: the distance between two points on a grid

Think of the legs as Δx and Δy.

8. The theorem does not apply to

Answer: a triangle with no right angle

All angles must include 90°.