Question

plz SOLVE ..... its urgent .... IT'S FROM CHAPTER-TRIANGLES OF CLASS 9

it's question 4 from ex.- 7.4



plzz. .... . . . I have test tomorrow ☺

Answer 1

the first image is to prove that angle A > angle B.
the second image is to prove angle B > angleD

Answer 2

here is your answer


4. AB and CD are respectively the smallest and longest sides of a quadrilateral ABCD
(See figure). Show that A > C and B > D.

Ans. Given: ABCD is a quadrilateral with AB as smallest and CD as longest side.

To prove: (i) A > C (ii) B > D

Construction: Join AC and BD. ( figure is in the pic )

Proof: (i) In ABC, AB is the smallest side.
.: < 4 < 2 ……….(i)

[Angle opposite to smaller side is smaller]

In ADC, DC is the longest side.

3 < 1 ……….(ii)

[Angle opposite to smaller side is smaller]

Adding eq. (i) and (ii),

4 + 3 < 1 + 2

C < A

=> A > C

(ii) In ABD, AB is the smallest side.

5 < 8 ……….(iii)

[Angle opposite to smaller side is smaller]

In BDC, DC is the longest side.

6 < 7 ……….(iv)

[Angle opposite to smaller side is smaller]

Adding eq. (iii) and (iv),

5 + 6 < 7 + 8

< D < B

=> B > D

hope this helps you ##