Question 675664
the sum of all angles in a quadrilateral {{{ABCD}}} is {{{360}}} degrees

so, {{{A+B+C+D=360}}} 

{{{(3x+5)+(3x-10)+(x+25)+(2x-15)=360}}} 

{{{3x+5+3x-10+x+25+2x-15=360}}} 

{{{9x+5=360}}} 

{{{9x=360-5}}}

{{{9x=355}}}

{{{x=355/9}}}

{{{x=39.444}}}


{{{A=3x+5}}}

{{{A=3*39.44+5}}}

{{{A=118.32+5}}}

{{{highlight(A=123.332)}}}


{{{B=3x-10}}}

{{{B=118.332-10}}}

{{{highlight(B=108.332)}}}


{{{C=x+25}}}

{{{C=39.444+25}}}

{{{highlight(C=64.444)}}}



{{{D=2x-15}}}

{{{D=2*39.444-15}}}

{{{D=78.888-15}}}

{{{highlight(D=63.888)}}}