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Pythagorean Theorem Worksheet Answer Key – Grade 8

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Last updated: October 22, 2026 · Written by the Math Made Easy math teachers

Grade 8 Math Worksheet Answer Keys – Mathbot, the Math Made Easy robot coach, with free printable worksheet answer keys for Grade 8

Looking for a pythagorean theorem worksheet answer key? Then this answer key gives every step of the Grade 8 worksheet on The Pythagorean Theorem and Its Converse. Each solution identifies the hypotenuse, writes the equation, and finishes with a root. Compare your sketch and your equation with the key, and check the final length: the hypotenuse must be longer than either leg.

Standards: 8.G.B.6, 8.G.B.7 · Level: Grade 8

Problem 2 Find a leg

b² = 17² − 8² = 289 − 64 = 225.

b = √225 = 15.

The other leg is 15.

Problem 3 Irrational hypotenuse

c² = 6² + 7² = 36 + 49 = 85.

c = √85 ≈ 9.22.

The hypotenuse is about 9.2.

Problem 4 Leg to the nearest tenth

b² = 13² − 9² = 169 − 81 = 88.

b = √88 ≈ 9.38.

The leg is about 9.4.

Problem 5 Is it a right triangle?

The longest side is 41. 9² + 40² = 81 + 1,600 = 1,681, and 41² = 1,681.

The sums are equal, so the converse applies.

Yes, it is a right triangle

Problem 6 Read the figure

7² + 24² = 49 + 576 = 625.

√625 = 25.

24725
The hypotenuse is 25.

Hypotenuse: 25

Problem 7 Not a right triangle

10² + 11² = 100 + 121 = 221, but 15² = 225.

The sums are not equal.

No, it is not a right triangle

Problem 8 Find x

x² = 34² − 16² = 1,156 − 256 = 900.

x = 30.

163034
x = 30.

x = 30

Problem 9 Areas of squares

The square on the hypotenuse has area 25 + 144 = 169.

Its side is √169 = 13.

The hypotenuse is 13.

Problem 10 Short ladder

h² = 10² − 3.5² = 100 − 12.25 = 87.75.

h = √87.75 ≈ 9.37.

It reaches about 9.4 feet.

Problem 11 TV size

48² + 27² = 2,304 + 729 = 3,033.

√3,033 ≈ 55.07.

The diagonal is about 55 inches.

Problem 12 Right or not?

1.5² + 2² = 2.25 + 4 = 6.25, and 2.5² = 6.25.

Yes, it is a right triangle

Problem 13 Across the field

45² + 108² = 2,025 + 11,664 = 13,689.

√13,689 = 117.

The diagonal is 117 yards.

Problem 14 Isosceles right triangle

c² = 12² + 12² = 288, so c = √288 = 12√2.

12√2 ≈ 16.97.

12√2 cm ≈ 17.0 cm

Problem 15 Fire truck ladder

h² = 26² − 10² = 676 − 100 = 576.

h = 24.

10 ft24 ft26 ft
The ladder reaches 24 ft.

The ladder reaches 24 feet.

Problem 16 Baseball throw

Home plate to second base is the diagonal of the square: d² = 60² + 60² = 7,200.

d = √7,200 ≈ 84.85.

The throw is about 84.9 feet.

Problem 17 Wheelchair ramp

Length² = 30² + 2.5² = 900 + 6.25 = 906.25.

Length = √906.25 ≈ 30.10.

The ramp is about 30.1 feet long.

Problem 18 Shipping box

d² = 12² + 16² + 21² = 144 + 256 + 441 = 841.

d = 29.

The longest rod is 29 inches.

Problem 19 Drone flight

Horizontal distance: √(36² + 15²) = √(1,296 + 225) = √1,521 = 39.

Straight-line distance: √(39² + 20²) = √(1,521 + 400) = √1,921 ≈ 43.83.

The drone is about 43.8 meters from the start.

Problem 20 Is the deck square?

2.4² + 3.2² = 5.76 + 10.24 = 16, so a right angle needs a diagonal of √16 = 4.

The measured 4.1² = 16.81, which does not equal 16.

No; the diagonal should be 4.0 meters