# Calculating angles using trigonometric ratios - Tutorial

math tutorials > calculating angles of a triangle using trig ratios

## The size of an unknown angle in a right-angled triangle can be calculated using the trigonometric ratios.

**What you will need: **

You will need to use the **INV
/ Shift / 2ndf** key on your **scientific calculator**.

## Steps

- Label the sides.
- Identify which trig. ratio uses these sides.
- Calculate the angle.

e.g.

## Trigonometry problems for you to try.

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