An item costs $ 390 before tax, and the sales tax is $31.20 . Find the sales tax rate. Write your answer as a percentage.

Step-by-step explanation:

390x=31.20

divide each side by 390

you get 0.08

multiply that by 100

you get 8%

look a the sides they are perpendicular

area of part 1:

a1=base*height/2=(8+2)*(8-2-2-1)/2=10*3/2=15 ft^2

area of part 2:

a2=length*width=(8+2)*1=10 ft2

area of part 3:

a3=length*width=8*2=16 ft2

total shaded area : a1+a2+a3=41 ft2

total area of the reactangle : a=16*8=128 ft2

total area of the nonshaded region : 128-41=87 ft2