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Pythagorean Theorem Worksheets

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Pythagorean theorem worksheets teach one of the most famous results in geometry: in a right triangle, a2 + b2 = c2. These free printable Pythagorean theorem worksheets cover finding the hypotenuse, finding a missing leg, testing whether a triangle is right, and word problems, with an answer key on every PDF and a maker for new problems.

Quick answer: The Pythagorean theorem says that in a right triangle the square of the hypotenuse equals the sum of the squares of the legs: a2 + b2 = c2. For legs 3 and 4, c = √25 = 5. This page has 7 free Pythagorean theorem worksheets (PDF) with answer keys for grade 8, plus a maker. Updated October 2026.

Ready-to-print samples

A few of the ready PDFs on this page. The full list is under Ready-to-print worksheets, and the maker above makes new problems on demand.

The Pythagorean theorem in three steps

  1. Identify the hypotenuse c: the longest side, opposite the right angle.
  2. Write a2 + b2 = c2 and substitute the two sides you know.
  3. Solve for the missing side by adding or subtracting the squares and taking the square root.

Pythagorean triples

Some right triangles have whole-number sides. These sets are called Pythagorean triples, and recognizing them speeds up many problems:

Legs a and b a2 + b2 c2 Hypotenuse c
3 and 4 9 + 16 = 25 25 5
5 and 12 25 + 144 = 169 169 13
8 and 15 64 + 225 = 289 289 17
7 and 24 49 + 576 = 625 625 25
20 and 21 400 + 441 = 841 841 29
6 and 8 36 + 64 = 100 100 10

Pythagorean theorem worksheet: finding the hypotenuse

Square both legs, add, and take the square root. Answers that are not perfect squares can be left as a radical or rounded:

Legs Square and add Take the square root Answer
6 and 8 36 + 64 = 100 √100 10
9 and 12 81 + 144 = 225 √225 15
10 and 24 100 + 576 = 676 √676 26
2 and 5 4 + 25 = 29 √29 about 5.39
4 and 7 16 + 49 = 65 √65 about 8.06

Find the missing side of a right triangle worksheet

When the hypotenuse is given, subtract the squares instead of adding them:

Hypotenuse and one leg Subtract the squares Take the square root Missing leg
c = 13, a = 5 169 − 25 = 144 √144 12
c = 10, a = 6 100 − 36 = 64 √64 8
c = 25, a = 7 625 − 49 = 576 √576 24
c = 17, a = 8 289 − 64 = 225 √225 15

Converse of the Pythagorean theorem worksheet

The converse says that if a2 + b2 = c2 for the three sides, the triangle has a right angle. Test the two shorter sides against the longest:

Sides a2 + b2 c2 Right triangle?
6, 8, 10 100 100 Yes
5, 11, 12 146 144 No
9, 40, 41 1,681 1,681 Yes
7, 9, 12 130 144 No

Try ten Pythagorean theorem problems

Use these as a warm-up. Draw the triangle first and label the hypotenuse.

# Problem Answer
1 Legs 9 and 12. Find the hypotenuse. 15
2 Legs 7 and 24. Find the hypotenuse. 25
3 Hypotenuse 26, one leg 10. Find the other leg. 24
4 Hypotenuse 15, one leg 9. Find the other leg. 12
5 Is 8, 15, 17 a right triangle? Yes: 64 + 225 = 289
6 Is 6, 9, 11 a right triangle? No: 36 + 81 = 117, not 121
7 Legs 5 and 5. Find the hypotenuse. √50, about 7.07
8 A 10 ft ladder reaches 8 ft up a wall. How far is the base from the wall? 6 ft
9 A rectangle is 12 by 16. Find its diagonal. 20
10 Legs 1 and 1. Find the hypotenuse. √2, about 1.41

Pythagorean theorem vocabulary

Students answer questions faster when they know the words. These are the terms used on the worksheets and answer keys:

Word Meaning Example
Hypotenuse The longest side of a right triangle, opposite the right angle c in a2 + b2 = c2
Legs The two shorter sides that meet at the right angle a and b
Right triangle A triangle with one 90-degree angle 3, 4, 5
Pythagorean triple Three whole numbers that satisfy the theorem 5, 12, 13
Converse The reverse statement, used to test for a right angle If 62 + 82 = 102, the triangle is right

Pythagorean theorem practice and word problems

This page is also searched as Pythagorean theorem practice, Pythagorean theorem problems, finding the hypotenuse worksheet and Pythagorean theorem word problems. All of them are the free PDFs above, with an answer key, for US Letter or A4, with no sign-up. The square root worksheets page covers the roots used to finish each problem.

How to use these Pythagorean theorem worksheets

Use the Pythagorean theorem worksheets in order. Start with the hypotenuse sheets until students can square and add without a calculator, then switch to the missing leg sheets, where the subtraction step is the new idea. Pythagorean theorem worksheets with a sketch work best, so ask students to draw and label every triangle.

Once the equation is automatic, use the Pythagorean theorem worksheets on right triangles and word problems for review. Print one of the Pythagorean theorem worksheets for homework, and use the answer key to check the work together the next day. Because every set can be regenerated, a student who needs more Pythagorean theorem worksheets can make a new one in seconds.

Common Core standards for the Pythagorean theorem

These worksheets practice the Common Core geometry standards for grade 8:

Grade Standard What students do
Grade 8 8.G.B.6 Explain a proof of the Pythagorean theorem and its converse
Grade 8 8.G.B.7 Apply the theorem to find unknown side lengths in right triangles, including real-world problems
Grade 8 8.G.B.8 Apply the theorem to find the distance between two points in a coordinate system

Common mistakes with the Pythagorean theorem

Mistake Example Fix
Adding the sides without squaring legs 3 and 4: c = 7 Square first: 9 + 16 = 25, so c = 5
Forgetting the square root c2 = 25 and c = 25 Take the root: c = 5
Using the wrong side as c a = 13, b = 5: 132 + 52 c is always the longest side, opposite the right angle
Adding when finding a leg c = 13, a = 5: b2 = 169 + 25 Subtract: b2 = 169 − 25 = 144, so b = 12
Applying the theorem to any triangle Used on a triangle with no right angle It works only for right triangles

Real-life uses of the Pythagorean theorem

Builders, designers and navigators use right triangles daily:

Situation Calculation Answer
A 13 ft ladder has its base 5 ft from a wall. How high does it reach? √(169 − 25) 12 ft
A TV is 24 in wide and 18 in tall. What is the diagonal? √(576 + 324) about 30 in
A ramp rises 3 ft over a 4 ft run. How long is the ramp? √(9 + 16) 5 ft
A baseball diamond has 90 ft sides. How far is home to second? √(8,100 + 8,100) about 127.3 ft
A rectangle is 15 by 20. What is its diagonal? √(225 + 400) 25

Which Pythagorean theorem worksheet should you start with?

Start with the hypotenuse, then missing legs. Add the converse and word problems once the equation is automatic. Set B gives a retest for the first two levels.

Level Skill Best for
Level 1 Find the hypotenuse Grade 8, first lesson
Level 2 Find a missing leg Grade 8
Level 3 Is it a right triangle? Grade 8
Level 4 Word problems Grade 8
Level 5 Answers that are not whole numbers Grade 8, extension

A weekly plan for the Pythagorean theorem

Day Focus Suggested block
Monday Find the hypotenuse 15 min
Tuesday Find a missing leg 15 min
Wednesday Right triangle test 15 min
Thursday Word problems 15 min
Weekly total Four short sessions 60 min

Frequently asked questions

5 quick answers

Where can I download free Pythagorean theorem worksheets?

Open any worksheet in the Ready-to-print list on this page, choose US Letter or A4, then print or save the PDF. They are free, with answer keys, and no account is needed.

What is the Pythagorean theorem?

In a right triangle, a2 + b2 = c2, where c is the hypotenuse and a and b are the legs.

How do you find a missing leg?

Subtract the square of the known leg from the square of the hypotenuse, then take the square root. For c = 13 and a = 5, b = √144 = 12.

How do you know if a triangle is a right triangle?

Check whether the squares of the two shorter sides add to the square of the longest side. If they do, it is a right triangle.

What grade learns the Pythagorean theorem?

It is a grade 8 standard, covered in 8.G.B.6, 8.G.B.7 and 8.G.B.8.

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