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Which of the following… (Class 10 Maths 2025, Q9)

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MathsCBSE Class 10 · Standard · Board exam 2025, set 30/2/1 · 1 mark · MCQ

CBSE Class 10 Mathematics Standard 2025: question 9

Set in the CBSE Class 10 board exam of 2025, paper 30/2/1, section A, question 9, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q9 · 1 mark · MCQTriangles

Which of the following statements is incorrect ?

  1. (A)Two congruent figures are always similar.
  2. (B)A square and a rhombus of the same area are always similar.
  3. (C)Two equilateral triangles are always similar.
  4. (D)Two similar triangles need not be congruent.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 30/2/1.

Hints

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

Hint 1

For two polygons to be similar, their corresponding angles must be equal.

Hint 2

Does a rhombus always have angles?

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.

  1. (A), (C) and (D) are true facts about similarity. Congruent figures have the same shape, all equilateral triangles have equal angles of , and similar triangles may differ in size.

    ½ mark

  2. A rhombus need not have right angles, so its angles may not match those of a square. Equal area does not make the two figures similar. So (B) is incorrect.

    ½ mark

Answer: Option (B)

Where the marks are

  • Recognises that a rhombus's angles need not equal , so (B) is the incorrect statement (1 mark)

Revise the chapter

  • Chapter: Triangles (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Triangles, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 30/2/1 (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.