70°
add the parts of the ratio 5 + 6 + 7 = 18
the sum of the 3 angles in a triangle = 180°
divide 180 by 18 to find 1 part of the ratio
[tex]\frac{180}{18}[/tex] = 10° ← 1 part of ratio
5 parts = 5 × 10 = 50°
6 parts = 6 × 10 = 60°
7 parts = 7 × 10 = 70° ← largest angle
note that 50° + 60° + 70° = 180° ← check
