Answer:
45° , 60° , 75°
Explanation:
sum the parts of the ratio , 3 + 4 + 5 = 12 parts
the sum of the 3 angles in a triangle is 180°
divide 180° by 12 to find the value of one part of the ratio
180° ÷ 12 = 15° , then
3 parts = 3 × 15° = 45°
4 parts = 4 × 15° = 60°
5 parts = 5 × 15° = 75°
the measures of the 3 angles are 45° , 60° , 75°