Q.7 The measure of an angle exceeds three times the measure of its supplement by ? 20 . Find its measure

Question

Q.7 The measure of an angle exceeds three times the measure of its supplement by ? 20 . Find its measure

 

Answer 1

An angle and it's supplement add to 180 degrees:  A + A_s = 180.

The supplement of an angle A_s = 180-A

 

A = 3A_s +20          substitute 180-A in place of A_s

A = 3(180-A)+20  distribute 3 through the parenthesis

A = 540-3A+20     add 3A to both sides

4A = 560              divide both sides by 4

A = 560/4

A = 140 degrees

 

Check answer:

A_s = 180-140 = 40   the supplemental angle is 40 degrees

 

A = 3A_s+20

140 = 3(40)+20

140 = 140