This document discusses how to use Pythagoras' Theorem to solve for the length of the hypotenuse or third side of a right triangle when two sides are known. It explains that Pythagoras' Theorem states that the square of the hypotenuse is equal to the sum of the squares of the other two sides. The document provides an example of using this theorem to calculate the missing side of a right triangle given the lengths of the other two sides.

1. RIGHT TRIANGLES
Solution of a right triangle when two
sides are known

2. Right angle

3. Triangle
 A shape
with 3 sides

4. Theorem
 A
mathematical
formula for
calculating
values.

5. Side

6. Length
 The measurement of the extent of
something along its greatest
dimension

7. Hypotenuse

8. “X square”

9. “Plus”

10. “Equal”

11. “Square root”

12. Procedure
 If the length of two
sides in a right-
angled triangle is
known, then the
length of the third
side can be
calculated using
Pythagoras’
Theorem.

13.  The first thing that we need to do is
to check whether we can use
Pythagoras’ Theorem or not.
 Does the triangle have right angle?
 Yes, it does

14. Are we given enough information?
 Since we are looking for a side, do
we have the length of the other two
sides?
Yes, we do.

15.  This rule states that the square on
the hypotenuse (what we are looking
for) is equal to the sum of the
squares on the other two sides, or
what we get when we square the
other two lengths and add them
together.

17. Using Pythagoras’ Theorem, we
get:


18. 

19. Practice:
 Say which of the following triangles is
really right-angled:
A) B) C)

20. Find the length of the missing
side
A) 10 cm B) 7 cm C) 8 cm

21. SUMMARY
