Geometry and measuresKey Stage 3

Choosing sine, cosine or tangent

Match a pair of sides to the correct trigonometric ratio.

  • is opposite the chosen angle. is the shorter side next to it. is opposite the right angle.
  • Choose the ratio that contains the two sides you need.
RatioSides
Opposite and hypotenuse
Adjacent and hypotenuse
Opposite and adjacent

Example 1

Find exactly.

Example 2

Find exactly.

Example 3

Find exactly.

Remember
Changing the chosen acute angle swaps opposite and adjacent. The hypotenuse stays the same.

Your turn

Question 1

Find exactly.

Check answer
Question 2

Find exactly.

Check answer
Question 3

Find exactly.

Check answer
Question 4

Find exactly.

Check answer
Question 5

Find exactly.

Check answer
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