Solve Problems Using Pythagoras' Theorem Worksheet

We already know that Pythagoras was a top bloke.

He did come up with the theorem on how to work out the length of sides for triangles after all.

wooly hat

Let us put our thinking cap on the revise the theorem

Remember this theorem only works for right-angled triangles.

To find the hypotenuse (longer side) of a triangle:

right angles triangle without hypotenuse length

10² + 3² = √109 = 10.44 cm to 2 decimal places

To find the shorter side length:

right angled triangle with shorter side length missing

9² - 7² =√32 = 5.66 to 2 decimal places

The key point here is to remember when to add and when to subtract.

Now, we are okay with using Pythagoras' theorem, we can apply this to solve all sorts of problems.

sketch book

IF IN DOUBT, SKETCH IT OUT!

I leave my house to go to the bus stop.

I walk 20 m due west and then walk another 30 m due north.

If I had taken the direct route how far would I have walked?

30 M___________

20 M

Here you can see a right-angled triangle has been formed.

The direct route would be the diagonal (hypotenuse)

20² + 30² = √1300 = 36.05 m

eye

You are always looking to sketch the situation out or turn a diagram into a right angles triangle.

How long is the diagonal of this sponge if the length is 10 cm and the width is 4 cm?

Round your answer to 2 decimal places.

This boat is taking tourists on a local cruise.

It leaves port and travels due west for 15 km and then due south for another 14 km to a different port.

How far would it have travelled if it had gone direct from port to port?

Answers have been rounded to 2 decimal places (2 d.p)

14.8 km

21.65 km

14.5 km

20.52 km

laddr

A ladder 10 m long is leaning against the wall of a house.

The ladder reaches 8 m up the wall of the house.

How far away from the base of the wall is the ladder?

14.8 km

21.65 km

14.5 km

20.52 km

material

George takes a rectangular piece of material and cuts 14 cm along the diagonal.

The width of the material is 7 cm.

What is the length of the material?

14.70 cm

12.12 cm

14.24 cm

11.06 cm

A blackbird has spotted a juicy worm for lunch.

The bird is in a tree that is 12 m high.

The worm is 14 m away from the base of the tree.

How far does the blackbird have to swoop to catch his lunch?

Round your answer to 2 decimal places.

14.70 cm

12.12 cm

14.24 cm

11.06 cm

child on a slide

The ladder on the slide is 1.5 m high, the slide itself is 4 m long.

How far away from the base of the steps does the slide reach?

Round your answer to 1 decimal place (1 d.p)

14.70 cm

12.12 cm

14.24 cm

11.06 cm

flamingo

There are four flamingos in each corner of a rectangular lake.

Two flamingos at the top of the lake want to walk along the edge of the lake to be with their mate.

One side of the lake measures 20 m and the diagonal across measures 25 m.

How far do the flamingos have to walk?

	12m	14m	15 m	18 m
Width of the lake is

Daniel is standing looking at this statue.

The statue is 10 m taller than Daniel who is standing 12 m away.

How far is the top of the statue from the top of Daniel's head?

Give your answer as a number and round your answer to 2 decimal places. (2 d.p)

	12m	14m	15 m	18 m
Width of the lake is

ANSWERS

Question 1

How long is the diagonal of this sponge if the length is 10 cm and the width is 4 cm?

Round your answer to 2 decimal places.

CORRECT ANSWER

EDDIE SAYS

Just sketch it out and draw a line through the diagonal to see the right angles triangle. Here we can see we need the hypotenuse so it is adding. 10² + 4² = √116 = 10.77 to 2 decimal places

ANSWERS

Question 2

This boat is taking tourists on a local cruise.

It leaves port and travels due west for 15 km and then due south for another 14 km to a different port.

How far would it have travelled if it had gone direct from port to port?

Answers have been rounded to 2 decimal places (2 d.p)

CORRECT ANSWER

20.52 km

EDDIE SAYS

Did you sketch this out? I always find it easier to do so. Your sketch should show a right-angled triangle with the hypotenuse to find. 15² + 14² =√ 421 = 20.52 km to 2 d.p. It clearly can't be option a or c as the lengths are shorter than the hypotenuse.

ANSWERS

Question 3

laddr

A ladder 10 m long is leaning against the wall of a house.

The ladder reaches 8 m up the wall of the house.

How far away from the base of the wall is the ladder?

CORRECT ANSWER

EDDIE SAYS

Your sketch should have shown you that this time you wanted a shorter side of the triangle. 10² - 8² = √36 = 6 m

ANSWERS

ANSWERS

Question 5

cat stuck in a tree

Your cat is stuck up a tree!

You put up a ladder of length 5 m to go and rescue it.

The base of the ladder is 2 m away from the tree.

As you get to the top of the tree, your cat decides to run down the tree trunk to safety.

How far did the cat run?

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

CORRECT ANSWER

EDDIE SAYS

Don't you just love it when cats do that? You were looking for a shorter side of the triangle here so it was a subtraction. 5² - 2² = √21 = 4.58 cm to 2 d.p I hope you didn't get stuck up there instead of the cat.

ANSWERS

Question 6

material

George takes a rectangular piece of material and cuts 14 cm along the diagonal.

The width of the material is 7 cm.

What is the length of the material?

CORRECT ANSWER

12.12 cm

EDDIE SAYS

Can you see how sketching things out makes it easier for us to spot whether we need to add or subtract? 14² - 7² = √147 = 12. 12 cm It clearly can't be option a or c as the lengths are longer than the hypotenuse.

ANSWERS

Question 7

A blackbird has spotted a juicy worm for lunch.

The bird is in a tree that is 12 m high.

The worm is 14 m away from the base of the tree.

How far does the blackbird have to swoop to catch his lunch?

Round your answer to 2 decimal places.

CORRECT ANSWER

EDDIE SAYS

Do you think the bird won, or did the worm get away? Pretty even I think! The sketch shows you need to find the hypotenuse so this is an add. 12² + 14² = √ 340 = 18.44 to 2 d.p

ANSWERS

Question 8

child on a slide

The ladder on the slide is 1.5 m high, the slide itself is 4 m long.

How far away from the base of the steps does the slide reach?

Round your answer to 1 decimal place (1 d.p)

CORRECT ANSWER

EDDIE SAYS

Are you getting used to when to add and when to take away? This is the part where students generally make the mistake, so it is always worth doing that sketch. 4² - 1.5² = √13.75 = 3.7 to 1 d.p

ANSWERS

Question 9

flamingo

There are four flamingos in each corner of a rectangular lake.

Two flamingos at the top of the lake want to walk along the edge of the lake to be with their mate.

One side of the lake measures 20 m and the diagonal across measures 25 m.

How far do the flamingos have to walk?

CORRECT ANSWER

	12m	14m	15 m	18 m
Width of the lake is

EDDIE SAYS

This sketch should give you a shorter side to find. 25² - 20² = √ 225 cm² = 15 cm I love flamingos, but don't think I could stand on one leg as long as they do. I wonder why they do that?

ANSWERS

Question 10

Daniel is standing looking at this statue.

The statue is 10 m taller than Daniel who is standing 12 m away.

How far is the top of the statue from the top of Daniel's head?

Give your answer as a number and round your answer to 2 decimal places. (2 d.p)

CORRECT ANSWER

EDDIE SAYS

This sounds more complicated than it is, as you see when you sketch it out it is just another right-angled triangle. 10² + 12² = √244 cm² = 15.62 m I wonder who the statue is?