Question

In triangle ABC angle A equal to twice angleB minus 40degree and angle B equal to angle C. Find the value of angel A, angle B and angle C.

Answer 1

Answer:

let the angle B = X

B=C ......given

angle B= angle C = x

from the condition,

angle A= 2x -40°

angle A+ angle B + angle C= 180°.....sum of measure of angles of a triangle

2x-40°+x+X= 180°

2x-40°+2x=180

4x=180-40

4x=140

X=140/4

X=35°

angle B= angle C= 35°

angle A =2x-40°

=2×35°-40°

=70°-40°

=30°

angle A = 30°