Sam worked on his science fair project for 1/4 hour on Friday in 1/2 hour on Saturday what are the four common denominators which are less than 20 for the fractions complete exclamation

there is 4, 8, 12, and 16. those are denominators

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