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
- Identify the hypotenuse c: the longest side, opposite the right angle.
- Write a2 + b2 = c2 and substitute the two sides you know.
- 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.
More math practice
- Square root worksheets for the roots.
- Exponents worksheets for squares.
- The coordinate plane for the distance between two points.