Answer:
y=42.3333333333 (repeating)
Explanation:
You need to find the corresponding side. You can see D H is corresponding to E C. So here is what you have to do, find x to (8x - 43) and (2x + 13).
2x + 13 + 8x - 43= 90
10x -30 = 90
+30 +30
10x = 120
/10 /10 = 12
to check if this is right take x which is 12 and plug it in.
8 x 12= 96 then 96 - 43= 53
2 x 21= 24 then 24 + 13= 37
Next you take 53 and 37 and add it together
53 + 37= 90
about that corresponding side, now you know D H and E C both equal 53
Now you can solve your equation.
53 + 2y + y= 180
53 + 3y = 180
-53 -53
3y = 127
/3 /3
y = 42.333333 (repeating)
to check if this is right take y which is 42.3333333 (repeating) and plug it in.
2y means to multiply y two times so...
42.3333333 (repeating)+ 42.33333333 (repeating)= 84.6666666 (repeating)
y = 42.333333333 (repeating)
E C = 53
add all the numbers together
42.333333 (repeating) + 84.66666666 (repating)+ 53= 180
Therefore y equals 42.33333333 (repeating)