# Use inverse functions to find an angle

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## Lesson details

### Key learning points

1. In this lesson, we will find a missing angle in a given triangle using the inverse trigonometric functions. We will need to interpret which trigonometric ratio to use, and rearrange it.

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## Video

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## Worksheet

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## Starter quiz

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### 3 Questions

Q1.
Use your calculator find the value of cos(56) to 3 decimal places.
0.560
0.829
Others
Q2.
Use your calculator find the value of tan(89) to 3 decimal places.
1.000
Error
Others
Q3.
3. Use your calculator to work out the size of sinѲ = 0.21 . Give your answer to one decimal place.
21.0 degrees
Error
Others

## Exit quiz

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### 3 Questions

Q1.
Which of the trigonometry ratios will be required to find the missing angle in this question?
inverse cosine
inverse tangent
Q2.