Given that depth of a swimming pool is = 8.5 meters
Now question says to find the half of depth in milimeters.
"half" basically means divide the given number by 2.
before doing that let's convert 8.5 meters into milimeters because final answer is requested in milimeters
we know that 1 meter = 1000 milimeters
So 8.5 meters = 8.5* 1000 = 8500 milimeters
Now we can divide 8500 by 2 find the required answer.
8500/2 = 4250
Hence final answer is 4250 meters.