Question 1205790
{{{4 }}}sided polygon with angles of 

{{{20x}}}, {{{8(2x+9)}}}, {{{36x }}}


 the sum of interior angles is always equal to {{{360}}} degrees


you got the measures of three angles, so the measure of the fourth angle is

{{{360-(20x+8(2x+9)+36x)=72 (4 - x)}}}


the sum of all angles will be

{{{360=(20x+8(2x+9)+36x)+72 (4 - x)}}}.....solve for {{{x}}}

{{{360=72x + 72+288 - 72 x}}}

{{{360=360}}}


so, the statement above will be true for ANY value of{{{ x}}}