approximate the volume of the backpack that is 17in × 12 in × 4in
if you need a picture I'll try to send it to help
To find volume you multiply all three dimensions by one another. We can approximate this by multiplying the smaller ones first.
124=48 Now multiply 48 by 10.
4810=480 We still have 7 to deal with, so we can multiply 48 by 2 and then by 5.
485=240
482=96
Now add the three together.
480+240+96=816.
Your answer is 816.
The formula for volume would make the equation 17" x 12" x 4", which would make it 816 cubic inches.