8th Grade The Pythagorean Theorem Worksheet (PDF)

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This pythagorean theorem worksheet for 8th Grade covers the pythagorean theorem (Common Core 8.G.B.6, 8.G.B.7), with a free PDF to print.

These 20 problems practice the Pythagorean theorem, its converse and applications in two and three dimensions (Common Core 8.G.B.6 and 8.G.B.7). Each problem has its own space for work, so print the page and write directly on it.

The problems start with direct skill checks and grow harder as you go. Later items use the converse, three dimensions and real situations such as ladders and ramps. Use the answer key afterwards to check every step.

Grade 8 · Common Core State Standards: 8.G.B.6, 8.G.B.7

Pythagorean theorem worksheet: exercises 1 to 10

Exercise 1 – Find the hypotenuse

6 in8 in?
A right triangle.

Find the hypotenuse of a right triangle with legs 6 inches and 8 inches.

Exercise 2 – Another triple

Find the hypotenuse of a right triangle with legs 5 and 12.

Exercise 3 – Find a leg

A right triangle has hypotenuse 17 and one leg 8. Find the other leg.

Exercise 4 – Not a whole number

Find the hypotenuse of a right triangle with legs 7 and 9. Round to the nearest tenth.

Exercise 5 – Is it a right triangle?

Is a triangle with sides 9, 12 and 15 a right triangle?

Exercise 6 – Not a right triangle

Is a triangle with sides 7, 8 and 12 a right triangle?

Exercise 7 – Ladder

? ft5 ft13 ft
A ladder leaning on a wall.

A 13-foot ladder leans on a wall with its base 5 feet from the wall. How high up the wall does it reach?

Exercise 8 – Rectangle diagonal

12 ft9 ft?
Half of a 12 ft by 9 ft rectangle.

A rectangular patio is 12 feet by 9 feet. How long is its diagonal?

Exercise 9 – TV screen

A TV screen is 40 inches wide and 24 inches tall. Find the diagonal measure to the nearest tenth.

Exercise 10 – Isosceles right triangle

A right triangle has two equal legs of length 10. Find the hypotenuse to the nearest tenth.

Exercises 11 and up

Exercise 11 – Perimeter

A right triangle has legs 9 and 12. Find its perimeter.

Exercise 12 – Test the converse

Use the converse to decide whether 20, 21 and 29 are the sides of a right triangle.

Exercise 13 – 3D box

1234?
A box with edges 3, 4 and 12.

Find the length of the space diagonal of a box with edges 3, 4 and 12.

Exercise 14 – Smaller box

Find the space diagonal of a box measuring 2 by 3 by 6.

Exercise 15 – Baseball diamond

90 ft90 fthomesecond? ft
Throw from home plate to second base.

The bases on a Little League field are 90 feet apart. How far is a throw from home plate to second base? Round to the nearest tenth.

Exercise 16 – Ramp

12 ft5 ft?
A ramp.

A ramp rises 5 feet over a horizontal distance of 12 feet. How long is the ramp?

Exercise 17 – Kite string

Diego flies a kite. The kite is 40 feet above the ground and 30 feet horizontally from Diego. How long is the string, ignoring Diego’s height?

Exercise 18 – Shortcut

A hiker walks 5 miles north and then 12 miles east. A straight path back is shorter. How many miles does she save by walking the direct path home?

Exercise 19 – Phone screen

A phone screen is 2.5 inches wide and 5.5 inches tall. Find its diagonal to the nearest tenth.

Exercise 20 – Explain

Liam says the theorem works for every triangle. Give a counterexample.

See the solutions: The Pythagorean Theorem worksheet solutions

Key facts behind this pythagorean theorem worksheet

Key facts
  • \(a^{2} + b^{2} = c^{2}\), where \(c\) is the hypotenuse.
  • To find a leg: \(a^{2} = c^{2} – b^{2}\).
  • Converse: if \(a^{2} + b^{2} = c^{2}\), the triangle has a right angle.
  • Common triples: 3-4-5, 5-12-13, 8-15-17 and their multiples.
  • The theorem works in 3D: the space diagonal satisfies \(d^{2} = a^{2} + b^{2} + c^{2}\).

How to use this pythagorean theorem worksheet

Work through the exercises in order: they go from simple to challenging. Write every step on paper, then compare with the solutions page and redo any exercise you missed the next day.

Download the pythagorean theorem worksheet as a PDF with the button below and keep it with your notes.

All Grade 8 chapters: Grade 8 math.

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8th Grade The Pythagorean Theorem Worksheet

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