Answer:
The surface of this wedge is 84 ft²
A is correct.
Explanation:
First we split the wedge into different figure. Please see the attachment for figure name.
Here we have total five figure.
We will find the area of each part and then add all together to find surface area.
Area of triangle, (Part A)
Area of rectangle, (Part B)
Area of triangle, (Part C)
Area of triangle, (Part D)
Area of triangle, (Part E)
Surface Area = A+B+C+D+E
Surface Area = 6+18+6+24+30 = 84 ft²
Hence, The surface of this wedge is 84 ft²