Question 1115910

A pentagon has {{{5}}} sides, and can be made from three triangles, so you know what  its interior angles add up to {{{3 * 180 = 540}}}°

When all angles are equal  and all sides are equal it is regular pentagon, otherwise it is irregular pentagon.

Regular and irregular polygons with the same number of sides will always have the same sum of interior angles, the difference only being that in a regular polygon, all interior angles have the same measurement. In an irregular polygon, some of the angles will be smaller, some of the angles will be larger, but they will still add up to the same number of degrees that are in the regular shape.

sum=(n-2)*180, where sum  is the sum of the interior angles of the polygon, and n equals the number of sides in the polygon

This method will work whether you are working with a regular or irregular polygon.

given: 
{{{140}}} degrees 
{{{76}}} degrees 
{{{y }}}degrees and 
{{{y }}} degrees are angles of a pentagon

since given the measure of two angles of a pentagon, there must be 3 remaining angles that are congruent
so, you have one more angle {{{y }}} degrees

 calculate{{{ y}}}:

{{{sum=(n-2)*180}}} -> {{{n=5}}}
{{{sum=(5-2)*180}}}
{{{sum=3*180}}}
{{{sum=540}}}°

{{{540=140+76+y+y+y}}}
{{{540-140-76=y+y+y}}}
{{{324=3y}}}
{{{y=324/3}}}
{{{y=108}}}°