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Sine, cosine and tangent
Free examples and worked answers. No account needed.
Practise the method.
Sine, cosine and tangent
Sine, cosine and tangent
Example 1
In a right triangle, the hypotenuse is 14cm and an acute angle is 30∘. Find the side x opposite that angle, in cm. Use sin30∘=0.5.
Right triangleDiagram not to scaleShow worked answer
Answer: 7
- sin30∘=hypotenuseopposite
- x=14×0.5=7cm.
Example 2
In a right triangle, the hypotenuse is 14cm and an acute angle is 60∘. Find the side x adjacent to that angle, in cm. Use cos60∘=0.5.
Right triangleDiagram not to scaleShow worked answer
Answer: 7
- cos60∘=hypotenuseadjacent
- x=14×0.5=7cm.
Example 3
In a right triangle, an acute angle is 45∘ and its adjacent leg is 5cm. Find the opposite leg x, in cm. Use tan45∘=1.
Right triangleDiagram not to scaleShow worked answer
Answer: 5
- tan45∘=adjacentopposite
- x=5×1=5cm.
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