# Finding side lengths

**Finding side lengths**

When one side of a triangle is given with the acute angle of a right-angled triangle, this information can be used to work out the lengths of the other sides using one of the trigonometric ratios. For example:

Find *x* to 2 decimal places

The hypotenuse is provided and the opposite side of the angle is to be determined. Therefore the following formula is used:

sin 0 = opposite / hypotenuse

sin 56º = *x / 12*

*x *= 12 x sin 56º

*x =* 9.95 cm* *