SOLUTION: In the figure above, side AC of triangle ABC lies on line l. What is the value of y? a. 22 b. 24 c. 25 d. 30 Link to image http://152.46.13.240/MoodleContent/SATprep/Mat

Algebra ->  Triangles -> SOLUTION: In the figure above, side AC of triangle ABC lies on line l. What is the value of y? a. 22 b. 24 c. 25 d. 30 Link to image http://152.46.13.240/MoodleContent/SATprep/Mat      Log On


   

Question 983225: In the figure above, side AC of triangle ABC lies on line l. What is the value of y?
a. 22
b. 24
c. 25
d. 30
Link to image
http://152.46.13.240/MoodleContent/SATprep/Math%20Unit%207/Lesson%203%20Notes%20Quiz/cb1.png
Answer by MathLover1(20855) About Me  (Show Source):
You can put this solution on YOUR website!

as you can see, 5y° is an external angle of triangle ABC
we know that 5y=180-x°
since angle B is 40°, and angle A=x and C=x, we have
x%2Bx%2B40=180°
2x=180-40°
x=140%2F2°
x=70°
so, angle A=70° and C=70°

then
5y=180-70°
5y=110°
y=110%2F5°
y=22°
so, your answer is: a. 22