The formula for the perimeter of a square is p=4s p is perimeter, 4 is the sides of the square, and s is the side length. So to fill it out, p=4(27) solve. Perimeter is 108cm.
80+10x is the expression. To find the cost for 9 guests, simply plug in 9 for x. This becomes an equation reading 80+10(9)=170. The total cost for 9 guests is $170.00.
