Find the measure of arc ab , and find the measure of segment dc .

Check the picture below, notice the tickmarks.

for a chord perpendicular to the diameter chord, their intersection makes two equal segements and those twin segments make twin arcs.

Answer for arc AB:

since we know FB is the perpendicular bisector of AC then we know AB is the same length as BC so: 2x + 5 = 3x - 2 put everything on the left side

2x + 5 + 2 = 3x -2 + 2    2x + 7 = 3x put the variables on one side

2x - 2x + 7 = 3x - 2x   7 = x  plug it in

2(7) + 5 = 19

AB = 19

Answer for segment DC:

since we know FB is the perpendicular bisector of AC then we know AD is the same as DC.

y + 8 = 5y put the variable on one side

y - y + 8 = 5y - y   8 = 4y simplify

8/4 = 4y/4

2 = y plug it in

5(2) = 10

DC = 10

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