Answer:
80°
Step-by-step explanation:
Let the angle be x then four times it's complement plus 60, that is
4(90 - x) + 60 ← is it's supplement
Supplementary angles sum to 180°
Sum the angle and it's supplement and equate to 180
x + 4(90 - x) + 60 = 180 ← distribute and simplify left side
x + 360 - 4x + 60 = 180
- 3x + 420 = 180 ( subtract 420 from both sides )
- 3x = - 240 ( divide both sides by - 3 )
x = 80
The required angle = x = 80°
supplement = 4(90 - 80) + 60 = 4 × 10 + 60 = 40 + 60 = 100°
