7. Triangles Class 9 Mathematics NCERT Exemplar Solutions (CBSE)

Chapter 7: Triangles – Class 9 Mathematics NCERT Exemplar Solutions (CBSE Board)

Chapter 7: Triangles

EXERCISE 7.1
In each of the following, write the correct answer:
1. Which of the following is not a criterion for congruence of triangles?
(A) SAS (B) ASA (C) SSA (D) SSS
2. If AB = QR, BC = PR and CA = PQ, then
(A) ∆ ABC ≅ ∆ PQR (B) ∆ CBA ≅ ∆ PRQ
(C) ∆ BAC ≅ ∆ RPQ (D) ∆ PQR ≅ ∆ BCA
3. In ∆ ABC, AB = AC and ∠B = 50°. Then ∠C is equal to
(A) 40° (B) 50° (C) 80° (D) 130°
4. In ∆ ABC, BC = AB and ∠B = 80°. Then ∠A is equal to
(A) 80° (B) 40° (C) 50° (D) 100°
5. In ∆ PQR, ∠R = ∠P and QR = 4 cm and PR = 5 cm. Then the length of PQ is
(A) 4 cm (B) 5 cm (C) 2 cm (D) 2.5 cm
6. D is a point on the side BC of a ∆ ABC such that AD bisects ∠BAC. Then
(A) BD = CD (B) BA > BD (C) BD > BA (D) CD > CA
7. It is given that ∆ ABC ≅ ∆ FDE and AB = 5 cm, ∠B = 40° and ∠A = 80°. Then which of the following is true?
(A) DF = 5 cm, ∠F = 60° (B) DF = 5 cm, ∠E = 60°
(C) DE = 5 cm, ∠E = 60° (D) DE = 5 cm, ∠D = 40°
8. Two sides of a triangle are of lengths 5 cm and 1.5 cm. The length of the third side of the triangle cannot be
(A) 3.6 cm (B) 4.1 cm (C) 3.8 cm (D) 3.4 cm
9. In ∆ PQR, if ∠R > ∠Q, then
(A) QR > PR (B) PQ > PR (C) PQ < PR (D) QR < PR
10. In triangles ABC and PQR, AB = AC, ∠C = ∠P and ∠B = ∠Q. The two triangles are
(A) isosceles but not congruent (B) isosceles and congruent
(C) congruent but not isosceles (D) neither congruent nor isosceles
11. In triangles ABC and DEF, AB = FD and ∠A = ∠D. The two triangles will be congruent by SAS axiom if
(A) BC = EF (B) AC = DE (C) AC = EF (D) BC = DE

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Posted 4 months ago