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#