Solve for X
Please walk me through the steps, I understand most of it I just forgot how to do it

x=8

Step-by-step explanation:

first you need to find the unknown corner so you do 180-71= 109

then find the interior angle degree (n-2)*180 (n=number of sides) so (4-2)*180=2(180)=360

then set everything equal to 360:

10x+6+13x-2+8x-1+109=360

(combine like terms)

31x+112=360

(subtract 112 form both sides)

31x=248

(divide both sides by 31)

x=8

it would open into a square depending on the type of envelope i’m not sure about the second part