SOLUTION: Quadrilateral- find the value of x. I have tried and tried to work this out and when I plug in my answer it doesnt figure. Please help I would appreciate it. (x+30)+(x-55)+(x-45)+

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Quadrilateral- find the value of x. I have tried and tried to work this out and when I plug in my answer it doesnt figure. Please help I would appreciate it. (x+30)+(x-55)+(x-45)+      Log On


   

Question 33519: Quadrilateral- find the value of x. I have tried and tried to work this out and when I plug in my answer it doesnt figure. Please help I would appreciate it.
(x+30)+(x-55)+(x-45)+ x=360 Thank you so very much!!
Answer by Cintchr(481) About Me  (Show Source):
You can put this solution on YOUR website!
+%28x%2B30%29%2B%28x-55%29%2B%28x-45%29%2Bx=360++
Combine like terms
+x%2Bx%2Bx%2Bx%2B30-55-45=360++
+4x-70=360++
Add 70 to both sides
+4x+=+430+
+x+=+430%2F4+
I reduced the improper fraction to make it easier to work.
+x+=+215%2F2+
CHECK:
+x%2Bx%2Bx%2Bx%2B30-55-45=360++
Use this to plug back in
+%28215%2F2%29%2B%28215%2F2%29%2B%28215%2F2%29%2B%28215%2F2%29%2B30-55-45=360++
Add the fractions
+%28860%2F2%29%2B30-55-45=360+
Reduce the fraction
+430%2B30-55-45=360+
Add and subtract left to right
+460-55-45=360+
+405-45=360+
+360=360+
YES!!!
So X DOES = 215/2 or 107.5 degrees