Answer:
Step-by-step explanation:
6). Surface area of a triangular prism = Area of the triangular bases + (Perimeter of the triangular base)×height
Area of one triangular base =
=
= 6 km²
Perimeter of the triangular base = (4 + 3 + 5)
= 12 km
Height of the triangular prism = 7 km
Surface area of the given triangular prism = 2(6) + (12)(7)
= 12 + 84
= 96 km²
7). Surface area of a rectangular prism = 2(lb + bh + hl)
Here, l = Length, b = Width and h = Height
By substituting the values from the given question,
l = 9 in, b = 9 in, h = 4 in
Surface area of the rectangular prism = 2(9×9 + 9×4 + 4×9)
= 2(81 + 36 + 36)
= 2(153)
= 306 in²