Answer:
m∠1= 80
m∠2= 100
m∠3= 80
Step-by-step explanation:
Given: m∠1= 2x +40
m∠2= 2y +40
m∠3= x +2y
m∠1 +m∠2= 180 (adj. ∠s on a str. line)
2x +40 +2y +40= 180
2x +2y+ 80= 180
2x +2y= 180 -80
2x +2y= 100
2(x +y)= 100
x +y= 100 ÷2
x +y= 50 -----(1)
m∠1= m∠3 (vert. opp. ∠s)
2x +40= x +2y
2x -x +40= 2y
x= 2y -40 -----(2)
Substitute equation (2) into (1):
2y -40 +y= 50
3y= 50 +40
3y= 90
y= 90 ÷3
y= 30
Substitute y= 30 into equation (2):
x= 2(30) -40
x= 60 -40
x= 20
m∠1
= 2x +40
= 2(20) +40
= 40 +40
= 80
m∠2
= 2y +40
= 2(30) +40
= 60 +40
= 100
m∠3
= x +2y
= 20 +2(30)
= 20 +60
= 80
Alternatively, since m∠1= m∠3,
m∠3
= m∠1 (vert. opp. ∠s)
= 80
