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🧾 CBSE · Class 9

Class 9 Maths: Triangles Worksheet (with Answers)

A free, print-ready worksheet on Triangles for CBSE Class 9 Maths, with a matching answer key. Use the sample below, or build your own with the exact mix of questions you need — no login, no ads.

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Sample worksheet

7 of 17 questions from this chapter. Generate your own for the full set, more variations, and a clean print layout.

  1. 1. Two figures are congruent if they have the:
    • (a) same perimeter only
    • (b) same area only
    • (c) same shape and size
    • (d) same shape only
  2. 2. Two sides and the included angle equal proves congruence by:
    • (a) RHS
    • (b) SAS
    • (c) ASA
    • (d) SSS
  3. 3. Which is NOT a valid congruence criterion?
    • (a) ASA
    • (b) RHS
    • (c) AAA
    • (d) SSS
  4. 4. In an isosceles triangle, the angles opposite the equal sides are:
    • (a) right angles
    • (b) equal
    • (c) unequal
    • (d) supplementary
  5. 5. State the SSS congruence criterion.
  6. 6. Why is AAA not a congruence rule?
  7. 7. Prove that the base angles of an isosceles triangle are equal (outline).
View answers
  1. 1. (c) same shape and size — Congruent means equal in both shape and size.
  2. 2. (b) SAS — Side–Angle–Side is the SAS criterion.
  3. 3. (c) AAA — AAA gives similar triangles, not necessarily congruent.
  4. 4. (b) equal — Base angles opposite equal sides are equal.
  5. 5. If the three sides of one triangle equal the three sides of another, the triangles are congruent.
  6. 6. Equal angles fix the shape but not the size, so AAA gives similar (not necessarily congruent) triangles.
  7. 7. Let triangle ABC have AB = AC. Draw the bisector AD of ∠A meeting BC at D. In triangles ABD and ACD: AB = AC (given), ∠BAD = ∠CAD (construction), AD = AD (common). By SAS, the triangles are congruent, so ∠B = ∠C — the base angles are equal.
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FAQ

Is this Class 9 Maths worksheet on Triangles free?
Yes — it is completely free, with no login and no ads. You can print it or save it as a PDF, and generate unlimited variations.
Does the Triangles worksheet come with answers?
Yes. Every worksheet has a separate answer key with the correct answers, short explanations and marks, so it is ready for marking.
Can I choose how many questions and which types?
Yes. Open the generator for this chapter and set how many MCQs, short, long and HOTS questions you want; totals and marks update live, and you can swap any single question.
Which board and class is this for?
This worksheet is aligned to CBSE Class 9 Maths, chapter “Triangles”.