Question

A = 11m, b = 8m and C = 2m for the triangle shown below.

Work out the value of x, giving your answer as an exact surd.
The diagram is not drawn accurately

Answer 1

x =
`√(53)`

Explanation:

Using Pythagoras' identity on the upper right triangle.

The square on the hypotenuse is equal to the sum of the squares on the other 2 sides.

Let the third side be d, then

d² + b² = a² , that is

d² + 8² = 11²

d² + 64 = 121 ( subtract 64 from both sides )

d² = 57

Using Pythagoras' identity on the lower right triangle, then

x² + c² = d²

x² + 2² = 57

x² + 4 = 57 ( subtract 4 from both sides )

x² = 53 ( take the square root of both sides )

x =
`√(53)`