Step-by-step explanation:
let the angles be ' 7x, 8x and 5x'
as we know, the sum of all the angles of a triangle is 180 degree, so,
7x + 8x + 5x = 180
20 = 180
x = 180/2
x = 90 degrees
7x = 7 × 90 = 630 degree
8x = 8 × 90 = 720 degrees
5x = 5 × 90 = 540 degrees
therefore, 5x is the smallest degrees