What is value of a in the below Triangles? Options are: A) 18 B) 20 C) 25 D) 36

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2 Answers
Apr 27, 2018

18.

Explanation:

In the DeltaCDA," side "DA has been extended to a point B.

:."Exterior "/_CAB"=Interiors"( /_CDA+/_ACD)=2a.

Similarly,

/_ABC=2a+3a=5a, and, /_ACB=2a+a=3a.

Since, in DeltaABC, /_ABC+/_ACB+/_CAB=180, we have,

5a+3a+2a=180.

rArr a=18.

Apr 27, 2018

a=18^0 (A)

Explanation:

/_ABC= 3 a+2 a=5 a ; /_BCA = a+2 a=3 a

/_CAB= a+ a=2 a

/_ABC+ /_BCA+/_CAB = 5 a+3 a+2 a=180 or

10 a =180 :. a =180/10= 18^0