This is the first presentation that our grade 8s will have on using Pythagoras' great theorem.

1. Investigating the
Pythagorean Theorem
Grade 8 Mathematics
Mr. J. Lingley

2. A Wise Man’s Theorem
leg
Pythagoras was an ancient
mathematician who was
born in 500 BC outside of
Athens Greece.
hypotenuse
leg
leg
• The Pythagorean Theorem describes only the right triangle.
• In a right triangle, the area of the square on the hypotenuse is
equal to the sum of the areas of the squares around the legs.
• The hypotenuse is always opposite of the right angle.

3. Where’s the Hypotenuse?

4. Find the length of the line
segment using Pythagoras’s help.
• Using the line as the
hypotenuse, complete the
right angle triangle.
• Around each of the
segments of the triangle,
draw squares.
• Try to find the length of
the ‘red line’

8. + =
• The squares around the two legs = the hypotenuse.
• If you know the area of the hypotenuse, then you
can find the side length by taking the square root.
• if you work backwards, you can find the length of a
leg.

9. Your Turn
Find the missing side lengths.
5 cm
?
10 cm
4 cm
4 cm
?
25 cm
?
15 cm