A bridge engineer needs to swap sin 23 deg for the matching ratio of its complement; which value is identical?

cos 67 deg. Complementary-angle rule: sin(t) = cos(90 - t). Put t = 23, so sin 23 deg = cos 67 deg.

Rewriting cos 31 deg through the angle that completes it to a right angle, what equal ratio appears?

sin 59 deg. Complementary-angle rule: cos(t) = sin(90 - t). Put t = 31, so cos 31 deg = sin 59 deg.

To merge two terms a coder substitutes tan 18 deg with the co-ratio of (90 - 18) deg; what does it become?

cot 72 deg. Complementary-angle rule: tan(t) = cot(90 - t). Put t = 18, so tan 18 deg = cot 72 deg.

Class 10 · Maths

Trigonometry MCQs

Take an interactive Trigonometry quiz for Class 10 Maths - tap an answer for instant feedback and a step-by-step solution. These are a few sample questions; practice the full Trigonometry set free on the RankByte app.

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Trigonometric ratios of complementary angles

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Trigonometric ratios of complementary angles

TrigonometryQuiz - Solve & Score

A few sample questions with instant answers and solutions - the full set is in the app.

Q1. A bridge engineer needs to swap sin 23 deg for the matching ratio of its complement; which value is identical?
- A.cos 67 deg
- B.sin 67 deg
- C.cos 157 deg
- D.cos 23 deg
Answer: A. cos 67 deg
Complementary-angle rule: sin(t) = cos(90 - t). Put t = 23, so sin 23 deg = cos 67 deg.
Q2. Rewriting cos 31 deg through the angle that completes it to a right angle, what equal ratio appears?
- A.sin 149 deg
- B.sin 59 deg
- C.cos 59 deg
- D.sin 31 deg
Answer: B. sin 59 deg
Complementary-angle rule: cos(t) = sin(90 - t). Put t = 31, so cos 31 deg = sin 59 deg.
Q3. To merge two terms a coder substitutes tan 18 deg with the co-ratio of (90 - 18) deg; what does it become?
- A.tan 72 deg
- B.cot 162 deg
- C.cot 18 deg
- D.cot 72 deg
Answer: D. cot 72 deg
Complementary-angle rule: tan(t) = cot(90 - t). Put t = 18, so tan 18 deg = cot 72 deg.