Can someone fix the incorrect problems?

First question: Answer is D

∵ Area of rectangle is L ⋅ W = 12 ⋅ 6 = 72

∵ Area of the shaded region is 36

∴ The area of the unshaded region =

the area of the whole rectangle - the shaded region =

72 - 36 = 36

∴ The area of the unshaded region = 36

Second question: Answer is A

∵ Area of triangle is Bh =

⋅ x ⋅ 4 = 32

∵ Height (h) = 4 ft

∴ Base (B) = ⋅ 2 = 8 ⋅ 2 = 16

∴ Base (B) = 16 ft

Third question: Answer is D

6.009 = 6 + 0.009

Fourth question: Answer is B

104.0032 = One hundred four and thirty-two ten-thousandths

Fifth question: Answer is B

∵ Perimeter of rectangle = 2(W+L) =

2(80+120) = 2 ⋅ 80 + 2 ⋅ 120 = 160 + 240 = 400

∴ He needs 400 of fencing