B is the answer
just like the picture
( T' is not exact. it just shows the reflection)
Answer is D.
When you have an exponent that is a fraction, the denominator is the number you root the base by. In this case the exponent is 3/5, so you fifth root 13 cubed.
The surface are would be 81 bc the base area is 9 and you have four triangles with the area of 18. Add them all up and you get 81
11,340 I believe. 5% of 8400 is 420. 420*7=2940 2940+8400=11340