A right-angled triangle has hypotenuse 10 cm and an angle of . Find the side opposite the angle.
SOH: O = sin θ × H.
Worked solution
- cm
GCSE & IGCSE maths practice
In a right-angled triangle, label the sides from the angle you're using: opposite, adjacent and hypotenuse. Then SOH CAH TOA: , , . To find an angle, use the inverse (, , ). Make sure your calculator is in degrees.
8 questions · Foundation tier · Every answer is checked as you type it, with a full worked solution. Updated .
| GCSE (AQA, Edexcel, OCR) | Foundation and Higher: know the trigonometric ratios and use them to find angles and lengths in right-angled triangles in 2D. Higher only: in 3D. |
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| Cambridge IGCSE (0580) | Core and Extended: apply Pythagoras' theorem and the sine, cosine and tangent ratios to right-angled triangles, including angles of elevation and depression. |
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A right-angled triangle has hypotenuse 10 cm and an angle of . Find the side opposite the angle.
SOH: O = sin θ × H.
Worked solution
The hypotenuse is 12 cm and the angle is . Find the adjacent side, to 3 significant figures.
CAH: A = cos θ × H.
Worked solution
The adjacent side is 8 cm and the angle is . Find the opposite side, to 3 significant figures.
TOA: O = tan θ × A.
Worked solution
The opposite side is 5 cm and the adjacent side is 9 cm. Find the angle, to 1 decimal place.
tan θ = 5/9.
Worked solution
The opposite side is 7 cm and the hypotenuse is 12 cm. Find the angle, to 1 decimal place.
sin θ = 7/12.
Worked solution
The opposite side is 6 cm and the angle is . Find the hypotenuse, to 3 significant figures.
H = O ÷ sin θ.
Worked solution
A 6 m ladder makes an angle of with the ground. How high up the wall does it reach, to 3 significant figures?
The height is opposite the 70° angle.
Worked solution
A tower is 40 m tall. From a point 65 m from its base, find the angle of elevation of the top, to 1 decimal place.
tan θ = 40/65.
Worked solution
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