5 cm 6 cm c Click here for the answe r Click here for the answe r Below is a right angled triangle. What is the length of side c?

a 2 + b 2 = c 2 a b c If you were able to answer the question on the previous page, chances are you used the Pythagorean theorem. If you were not able to answer the question, the next few pages will help.

Pythagoras was a Greek philosopher and mathematician. You are going to find out how he came up with his theory on right-angled triangles.

Using the triangle tool, draw a small right-angled triangle in the box below.

Your triangle should look something like this. Now draw three squares using the sides of the triangle as the first side of each square.

Your diagram should look like this. Now measure the sides a,b and c using the ruler provided. a b c sidelength a b c Your diagram should look like this. Now measure the sides a,b and c using the ruler provided.

a b c sidelength a b c squared Now find out the area of each square. Do this by squaring the length of the corresponding side.

a b c a 2 + b 2 = ________ c 2 = _______ If you add together the length of sides a and b squared what do you notice?

a b c a 2 + b 2 = c 2 b 2 = c 2 - a 2 a 2 = c 2 - b 2 You should notice that a 2 plus b 2 is the same as c 2. If you know the length of two sides of a triangle, you can figure out the length of the third side.

The following pages are answers to the tasks in the lesson activity.

5 cm 6 cm 7.81 cm Click here to go back Click here to go back Below is a right angled triangle. What is the length of side c?