Question

Class - 7
maths
calculate the angles of triangles ABC having 3 angles B= 4 angle C and interior angle A = 3/7 of an exterior angle A

Answer 1

In a triangle ABC angle C =3 angle B = 2 (angle A+ angle B). What are the three angles?

C = 2(A+B)

C = 3B, or

2(A+B) = 3B, or

2A+2B=3B, or

B=2A.

C =2(A+2A) = 6A

A+2A+6A = 180 or 9A = 180.

Or A = 20 deg. B = 40 deg, C = 120 deg.