The sum of the angles in any triangle is 180º. This property can be used to calculate missing angles in triangles.

The hypotenuse of a right-angled triangle is its longest side and is always opposite the right angle. The square of the hypotenuse can be found by adding the squares of the other two sides of the triangle.

1

State the sum of the angles in a triangle.

2

Use the given diagram to calculate the value of x.

3

Find the value of x in the given triangle.

4

Calculate the value of x.

5

Use the given triangle to show that the angles in a triangle add up to 180º.