In triangle ABC, angle A is three times as large as angle B. The exter

Question

In triangle ABC, angle A is three times as large as angle B. The exterior angle at C is 100°. Find the number of degrees in angle A.

(A) 20
(B) 25
(C) 50
(D) 60
(E) 75

randomavoidplease · Answer

Since Angle A + Angle B = Exterior Angle C
Then 4A = 100 Thus A = 25. A =3*25 Thus E .

Edited:

Deepakjhamb · Answer

answer is e ) 75

exterior angle = 3x+ x = 4x

4x = 100

x=25 , so a = 3*25 =75

Shadyshades · Answer

The answer is 75 degree.

A+B= ext C=100
A=3B
4B=100
B=25
A=75

Abhishek009 · Answer

Internal Angle of C is 80°

So, Sum of Internal Angles of A & B is 100°

A = 3B

Now,  3B + B = 100°

So,  B = 25°  &  A = 75° , Answer must be (E)

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