NCERT Class 9 Solutions: Triangles (Chapter 7) Exercise 7.2 – Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

Glide to success with Doorsteptutor material for CBSE : fully solved questions with step-by-step explanation- practice your way to success.

Diagram of Isosceles Triangle: In Isosceles Triangle, the two sides are equal.

Give Isoceles Triangle That Two Side Are Same

Q-5 ABC and DBC are two isosceles triangles on the same base BC (see Fig) . Show that .

ABC and DBC Are Two Isosceles Triangles


Given, ABC and DBC are two isosceles triangles.

To show,

Proof, In


(ABC is an isosceles triangle.)

(BCD is an isosceles triangle.)

Therefore, (By SSS congruence condition) .

Thus, (By Corresponding Part of Congruent Triangles) .

Q-6 ΔABC is an isosceles triangle in which . Side BA is produced to D such that AD = AB (see Fig. 7.34) . Show that is a right angle.

Triangle ABC is Isosceles


Given, and

To show, is a right angle.

Proof, In (Given) (Angles opposite to the equal sides are equal.) In , (Angles opposite to the equal sides are equal.)

Now, In , equation (1)

Similarly, in , equation (2) also, (BD is a straight line.)

Adding (i) and (ii)