Topics · Edexcel GCSE Maths (1MA1)
Sine, cosine or tangent depends only on which two sides the question involves. Label them from the angle, then choose.
ABC is a right-angled triangle.
Angle ABC = 90°, AC = 12 cm and angle BAC = 35°.
Work out the length of BC.
Give your answer correct to 1 decimal place.
See why
Which side is opposite the marked angle, and which is the hypotenuse?
Tap the side opposite the marked angle.
Adjacent is the side left over: next to the angle, but not the hypotenuse.
Now a fresh one
A ramp rises 1.5 m over a horizontal distance of 8 m.
Work out the angle between the ramp and the horizontal ground.
Give your answer correct to 1 decimal place.
Learn it properly
Where it comes up in the exam
- Specification G20: know the trigonometric ratios and apply them to find angles and lengths in right-angled triangles.
- On both tiers. Exact values such as sin 30° = 0.5 are expected on the non-calculator paper (G21).
- Pearson's examiners report students using a rule on the wrong triangle or the wrong pair of sides.