Answer:
324 km²
Step-by-step explanation:
The prism shown is a square pyramid
The volume of a square pyramid can be calculated by using this formula

where l = length of base, w = width of base and h = height
We are given the following dimensions...
length of base = 9 km
width of base = 9 km
height = 12 km
To find the volume of the pyramid, we plug in these given values into the formula
Hence,

V = 324
The y intercept is where it crosses the x axis. <span />