A rectangular prism is just a shape that looks like a brick.
If you think about a brick for a few seconds, you'll realize
that it has
-- 2 faces of (length by width)
-- 2 faces of (length by height)
and
-- 2 faces of (width by height).
The dimensions of the brick in question 6 are 8ft, 3ft, and 5ft.
So it has
-- 2 faces of 8ft by 3ft
-- 2 faces of 8ft by 5ft
and
-- 2 faces of 3ft by 5ft .
Can you take over and complete it now ?
1/15
1/9:5/3 = 3/45:1
3:45 = 1/15
7 x *cross multiply
-- = --
11 121
11x 847 *divide
--- = -----
11 11
x = 77
