NCERT Class 9 Solutions: Triangles (Chapter 7) Exercise 7.1 – Part 1

  • Previous

Side-Angle-Side congruent

Give Side-Angle-Side congruent rule ,so ∠B=∠Y and ∠C=∠Z.so,BC=YZ

Give Side-Angle-Side Congruent Rule

Give Side-Angle-Side congruent rule ,so ∠B=∠Y and ∠C=∠Z.so,BC=YZ

Corresponding Parts of Congruent Triangles

Corresponding Parts of Congruent Triangles is ABC and A'B'C'

Give Corresponding Parts of Congruent Triangles

Corresponding Parts of Congruent Triangles is ABC and A'B'C'

Q-1 In quadrilateral ACBD , AC=AD and AB bisects A (see Fig). Show that ABCABD .What can you say about BC and BD

Give ABCD quadrilateral,AC=AD and bisect ∠A and also △ABC≅△ABD

Give ABCD Quadrilateral,AC=AD

Give ABCD quadrilateral,AC=AD and bisect ∠A and also △ABC≅△ABD

Solution:

Given: In the quadrilateral ABCD, AC=AD and AB bisects A

Prove: ABCABD

Now,

AB=BA (Common line)

AC=AD (Given AB bisects A )

CAB=DAB (By Side-Angle-Side congruent rule)

ABCABD (By Corresponding Parts of Congruent Triangles)

BC=BD

Therefore, BC and BD are of equal lengths.

Q-2 ABCD is a quadrilateral in which AD=BC and DAB=CBA (see Fig.). Prove that

  1. ΔABDΔBAC

  2. BD=AC

  3. ABD=BAC.

Solution:

Give ABCD is a quadrilateral in which AD=BC and ∠DAB = ∠CBA

Give ABCD Is a Quadrilateral

Give ABCD is a quadrilateral in which AD=BC and ∠DAB = ∠CBA

Give

  1. In ΔABDΔBAC,

    • AB=BA (Common line)

    • DAB=CBA (Given)

    • AD=BC (Given)

    • Therefore, ΔABDΔBAC by Side-Angle-Side congruence condition.

  2. Since, ΔABDΔBAC

    • Therefore BD=AC by CPCT

  3. Since, ΔABDΔBAC

  • Therefore ABD=BAC (by Corresponding Parts of Congruent Triangles)

Explore Solutions for Mathematics

Sign In