Answer:
greatest angle = 90°
Explanation:
sum the parts of the ratio , 1 + 2 + 3 = 6 parts
the sum of the 3 angles in a triangle = 180°
divide 180° by 6 to find the value of one part of the ratio.
180° ÷ 6 = 30°
the greatest angle is the 3 parts of the ratio, then
greatest angle = 3 × 30° = 90°