2A = 3 A is true, when the measure of ∠ A is : (A) 90° (B) 60° (C) 45° (D) 30°

MathsCBSE Class 10 · Standard · Board exam 2025, set 30/4/1 · 1 mark · MCQ

CBSE Class 10 Mathematics Standard 2025: question 8

Set in the CBSE Class 10 board exam of 2025, paper 30/4/1, section A, question 8, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q8 · 1 mark · MCQIntroduction to Trigonometry

$tan 2 A = 3 tan A$ is true, when the measure of $∠ A$ is :

(A) $9 0^{\circ}$
(B) $6 0^{\circ}$
(C) $4 5^{\circ}$
(D) $3 0^{\circ}$

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 30/4/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Substitute each option.

Hint 2

Recall $tan 3 0^{\circ} = 1/ 3$ , $tan 6 0^{\circ} = 3$ .

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

For $A = 3 0^{\circ}$ : $tan 6 0^{\circ} = 3$ and $3 tan 3 0^{\circ} = \frac{3}{3} = 3$ . Equal.
1 mark
Others fail ( $tan 9 0^{\circ}$ undefined, $tan 12 0^{\circ} < 0$ , $tan 9 0^{\circ}$ for 45°). Option (D).

Answer: $3 0^{\circ}$ , option (D)

Where the marks are

Verifies $tan 6 0^{\circ} = 3 tan 3 0^{\circ}$ (1 mark)

Revise the chapter

Chapter: Introduction to Trigonometry (notes, formulas, where marks are lost and every past question)
Topic: Trigonometric Ratios of an Acute Angle

Practise this chapterBoard-style questions from Introduction to Trigonometry, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 30/4/1 (Standard): every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.

CBSE Class 10 Mathematics Standard 2025: question 8

Hints

Step-by-step solution

Revise the chapter

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