We know that the sum of all angles in any triangle is always 180 and we know that:
The smallest angle = x
Angle 2 = x + 35
Angle 3 = 3 * x
So:
180 = x + x + 35 + 3 * x
180 = x + x + 35 + 3x
180 = 2x + 35 + 3x
180 = 5x + 35 / - 35 (both sides)
145 = 5x / ÷ 5 (both sides)
x = 29
The smallest angle = 29
Angle 2 = 29 + 35 = 64
Angle 3 = 3 * 29 = 87
Check:
29 + 64 + 87 = 180, so it's correct :)