Right triangles

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.

16. Using Pythagoras’ Theorem, we get:  

17. If: Then: Z= 3.605551275 Therefore, to the nearest whole number: Z= 4  

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

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

20. SUMMARY Pythagoras’ Theorem applies to all right-angled triangles. This theorem says that in a right-angled triangle, with the hypotenuse labeled H, then The theorem works both ways. This means that if a triangle obeys Pythagoras’ Theorem, then it must be right-angled.