Question

In a pentagon, two angles are 40° and 60°, and the rest are in the ratio 1 : 3 : 7. Find the biggest angle of the pentagon.

Answer 1

In a pentagon, two angles are 40° and 60° Sum of remaining 3 angles

= 3 × 180° 

= 540° – 40° – 60° 

= 540° – 100°

= 440°

Ratio in these 3 angles = 1 : 3 : 7

Sum of ratios = 1 + 3 + 7

= 11

Biggest angle = `(440 xx 7)/11`

= 280°