Question 198287
Recall (or look up) that a sum of all the angles of a quadrilateral is ALWAYS 360 degrees.



So algebraically, this means that: {{{(x+5)+(x+10)+(x-10)+(2x-5)=360}}}



{{{(x+5)+(x+10)+(x-10)+(2x-5)=360}}} Start with the given equation.



{{{x+5+x+10+x-10+2x-5=360}}} Remove the parenthesis.



{{{5x=360}}} Combine like terms on the left side.



{{{x=(360)/(5)}}} Divide both sides by {{{5}}} to isolate {{{x}}}.



{{{x=72}}} Reduce.



Since {{{x=72}}}, we can find the angles to be: 



Angle #1: {{{x+5=72+5=77}}}


Angle #2: {{{x+10=72+10=82}}}


Angle #3: {{{x-10=72-10=62}}}


Angle #4: {{{2x-5=2(72)-5=144-5=139}}}



So we have the angles 77, 82, 62, and 139.



We can clearly see that the fourth angle of 139 degrees is the largest.