Suppose ABC be a triangle such that ∠A = 4x + 7 ,
∠B = 3x + 5 & ∠C = 6x + 12
We know, the sum of interior angles of a Triangle is 180°, therefore, ∠A + ∠B + ∠C = 180°
or, 4x + 7 + 3x + 5 + 6x + 12= 180°
or, 13x = 180 - 24
or, x = 156/ 13 = 12
