Find the Hypotenuse Using Pythagoras' Theorem Worksheet

thinking

Guess who

I was born 2500 years ago on the island of Samos

At the age of 18, I went to work for an astronomer

At the age of 21, I went to Egypt to learn about geometry

On my return to Greece, I opened a school in mathematics, music, philosophy and astronomy

I was famous for being a thinker.

Hello...Yes, it's me of course Pythagoras.

pythagoras

I am going to introduce you to my most well-known theorem.

Pythagoras' Theorem is a way of finding the length of the hypotenuse of a right-angled triangle.

Find the length of c

Follow these steps.

1. Take the number from 1 side and square it. 2 x 2 = 4

2. Take the number from the other side and square it. 6 x 6 = 36

3. Add your answers together 4 + 36 = 40

4. Square root (√) 40 = 6.32 to 2 decimal places.

check list

By the way, this only works for right-angled triangles.

Check

The hypotenuse is always the longest side of a triangle.

So if your answer is smaller than any of the other sides you have made a mistake.

The formula is a² + b² = c²

boy

What do you call a pot of boiling water at the top of Mount Everest?

High Pot in Use.

What is the length of C?

The answer has been rounded to 2 decimal places.

7.54

5.84

6.54

8.54

find the hypotenuse

Calculate the length of C.

Round your answer to 2 decimal places (2 d.p)

right angles triangle

Round your answer to 2 decimal places (2 d.p)

pythagoras triangle

What is the value of c?

Round your answer to 2 decimal places. (2 d.p)

Can you match the correct triangle with the correct hypotenuse?

Column A	Column B
Right angled triangle with sides 4 cm and 5 cm	Hypotenuse is 9.22 cm
Right angled triangle with sides 3 cm and 5 cm	Hypotenuse is 6.71
Right angled triangle with sides 6 cm and 7 cm	Hypotenuse is 5.83 cm
Right angled triangle with sides 6 cm and 3 cm	Hypotenuse is 6.40 cm

rectangle

What is the length of the diagonal of this triangle?

The length of the rectangle is 8 cm and the width is 4 cm.

	8.58 cm²	8.38 cm²	8.94 cm²	9.28 cm²
Length of diagonal

isosceles triangle

The base of this triangle is 12 cm and the height is 8 cm.

What is the length of the slanted side?

	8.58 cm²	8.38 cm²	8.94 cm²	9.28 cm²
Length of diagonal

Did you know that the size of a TV screen is determined using Pythagoras Theorem?

The size is measured by the hypotenuse of the television.

What is the size of this TV Screen?

The base is 45 inches and the height is 30 inches

34 inches

44 inches

54 inches

24 inches

smart phone

What is the screen size of this smartphone?

The base is 4 cm and the height is 7 cm.

Round your answer to 2 decimal places (2 d.p)

34 inches

44 inches

54 inches

24 inches

ANSWERS

Question 1

What is the length of C?

The answer has been rounded to 2 decimal places.

CORRECT ANSWER

8.54

EDDIE SAYS

So did you find not trying to use the formula easier? 8² + 3² = 73 √73 = 8.54 Pythagoras was a top bloke you know.

ANSWERS

Question 2

find the hypotenuse

Calculate the length of C.

Round your answer to 2 decimal places (2 d.p)

CORRECT ANSWER

7.21

EDDIE SAYS

6 x 6 = 36 4 x 4 = 16 36 + 16 = 52 √50 = 7.21 Did you know Pythagoras never wrote down his famous theory? He must have been clever.

ANSWERS

Question 3

right angles triangle

Round your answer to 2 decimal places (2 d.p)

CORRECT ANSWER

EDDIE SAYS

Square, square, add and square root. That's all there is to it. SSAS 7 x 7 = 49 5 x 5 = 24 49 + 25 = 74 √74 = 8.60

ANSWERS

Question 4

pythagoras triangle

What is the value of c?

Round your answer to 2 decimal places. (2 d.p)

CORRECT ANSWER

10.44

EDDIE SAYS

Square, Square, Add, Square root You can write you answers in various ways such as: 3 x 3 = 9 10 x 10 = 100 100 + 109 = 109 √ 109 = 1.44 Or 3² + 10² = √109 = 10.44 Pythagoras wouldn't mind either way.

ANSWERS

Question 5

Can you match the correct triangle with the correct hypotenuse?

CORRECT ANSWER

Column A	Column B
Right angled triangle with sides ...	Hypotenuse is 6.40 cm
Right angled triangle with sides ...	Hypotenuse is 5.83 cm
Right angled triangle with sides ...	Hypotenuse is 9.22 cm
Right angled triangle with sides ...	Hypotenuse is 6.71

EDDIE SAYS

Are you checking that the hypotenuse is always longer than the other sides? This is a good way to check if you are correct. Square side 1 + square side 2. Add your answers together. √ your answer

ANSWERS

Question 6

rectangle

What is the length of the diagonal of this triangle?

The length of the rectangle is 8 cm and the width is 4 cm.

CORRECT ANSWER

	8.58 cm²	8.38 cm²	8.94 cm²	9.28 cm²
Length of diagonal

EDDIE SAYS

But this isn't a triangle I hear you say! Well spotted, all you have to do is draw the diagonal line in and you will spot the right-angled triangle. 8² + 4² = √80² = 8.94 cm

ANSWERS

Question 7

isosceles triangle

The base of this triangle is 12 cm and the height is 8 cm.

What is the length of the slanted side?

CORRECT ANSWER

EDDIE SAYS

Hang on, this is not a right-angled triangle... but, we can make it one. We just draw a line down from the point to the base to create two right angles triangles. We know the height is 8 cm BE CAREFUL here as we have been given the base of the triangle as 12 cm but as we have cut it in 2 we only want half which is 6 cm. 6² + 8² = 100 √100 = 10

ANSWERS

Question 8

Did you know that the size of a TV screen is determined using Pythagoras Theorem?

The size is measured by the hypotenuse of the television.

What is the size of this TV Screen?

The base is 45 inches and the height is 30 inches

CORRECT ANSWER

54 inches

EDDIE SAYS

Imagine a diagonal line through the TV screen to create a right-angled triangle. 30 x 30 = 900 inches 45 x 45 = 2025 inches 900 + 2025 = 2925 √5625 = 54 inches Wow, that's a big TV. I wonder if all those years ago Pythagoras knew what his theorem would be used for!?

ANSWERS

Question 9

smart phone

What is the screen size of this smartphone?

The base is 4 cm and the height is 7 cm.

Round your answer to 2 decimal places (2 d.p)

CORRECT ANSWER

EDDIE SAYS

Just look on how to turn this into a right-angled triangle. Yes, draw an imaginary line on the diagonal. You don't want to draw a real one as it would annoy you trying to read the screen. 7² + 4² = 65² √65 =8.06 cm

ANSWERS

Question 10

triangles

EDDIE SAYS

See you can do two things at once now! Good old Pythagoras. He certainly knew what he was doing. 8² + 8² = 128 √ 128 = 11.31 cm 12² +12² = 288 √ 128 = 16.97 cm