10 questions · Form 3 Mathematics Bab 5: Trigonometric Ratios
10 questions · plays in fullscreen
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Convert 37.5° into degrees and minutes.
Answer: B
0.5° × 60' = 30'. Thus, 37.5° = 37° 30'.
2. Given a right-angled triangle with adjacent side = 5 cm and opposite side = 12 cm, calculate the hypotenuse length using Pythagoras theorem, then find cos θ.
Answer: B
Hypotenuse = √5² + 12² = √25 + 144 = √169 = 13 cm. cos θ = Adjacent / Hypotenuse = 513.
3. Calculate the value of sin 30° + cos 60°.
Answer: A
sin 30° = 12 and cos 60° = 12. Therefore, 12 + 12 = 1.
4. Convert 42° 18' into decimal degrees.
Answer: B
18' / 60 = 0.3°. Therefore, 42° 18' = 42.3°.
5. If cos θ = 0.5, what is the value of tan θ?
Answer: C
cos θ = 0.5 implies θ = 60°. tan 60° = √3 ≈ 1.732.
6. In triangle ABC, ∠B = 90°, AB = 9 cm, and AC = 15 cm. Find the value of sin ∠ACB.
Answer: A
For angle ∠ACB, opposite side is AB (9 cm) and hypotenuse is AC (15 cm). sin ∠ACB = 915 = 0.6.
7. What is the ratio formula for tan θ?
Answer: C
By definition, tangent is the ratio of the length of the opposite side to the length of the adjacent side (tan θ = OA).
8. What is the exact value of tan 45°?
Answer: C
In an isosceles right-angled triangle with acute angles of 45°, opposite side = adjacent side, so tan 45° = 1.
9. If cos θ = 0.8 in a right-angled triangle with hypotenuse 15 cm, calculate the length of the adjacent side.
Answer: A
cos θ = Adjacent / Hypotenuse => 0.8 = Adjacent / 15 => Adjacent = 0.8 × 15 = 12 cm.
10. What is the exact value of cos 60°?
Answer: A
From the special angles ratio table, cos 60° = 12 = 0.5.