Post-assessment |CBSE | G9 | C.7 Triangles

In triangle ABC, if AB=BC and ∠B = 70°, ∠A will be

• 70°

• 110°

• 55°

• 130°

For two triangles, if two angles and the included side of one triangle are equal to two angles and the included side of another triangle. Then the congruency rule is:

• SSS

• ASA

• SAS

• None of the above

ABC is an isosceles triangle in which altitudes BE and CF are drawn to equal sides AC and AB, respectively. Then

• BE > CF

• BE < CF

• BE = CF

• None of the above

In triangles ABC and PQR, AB = AC, ∠C = ∠P and ∠B = ∠Q. The two triangles are

• Isosceles and congruent

• Isosceles but not congruent

• Congruent but not isosceles

• Neither congruent nor isosceles

It is given that ∆ ABC ≅ ∆ FDE and AB = 5 cm, ∠B = 40° and ∠A = 80°. Then which of the following is true?

• DF = 5 cm, ∠F = 60°

• DF = 5 cm, ∠E = 60°

• DE = 5 cm, ∠E = 60°

• DE = 5 cm, ∠D = 40°

In triangles ABC and PQR, ∠𝐴 = ∠𝑄 𝑎𝑛𝑑 ∠𝐵 = ∠𝑅, Which side of ∆𝑃𝑄𝑅 should be equal to side AB of ∆𝐴𝐵𝐶 so that the two triangles are congruent? Give reason for your answer.

In ∆𝑃𝑄𝑅, ∠𝑃 = 70° and ∠𝑄 = 30°. Which side of this triangle is the longest?

Is it possible to construct a triangle with lengths of its sides 5cm, 3cm and 8cm? Give reason for your answer.

In Figure, it is given that AB = CF, EF = BD and ∠𝐴𝐹𝐸 = ∠𝐶𝐵𝐷. Prove that ∆𝐴𝐹𝐸 ≅ ∆𝐶𝐵𝐷.

S is any point on side QR of a ∆𝑃𝑄𝑅. Show that: 𝑃𝑄 + 𝑄𝑅 + 𝑅𝑃 > 2𝑃𝑆.