Question

How the volume answer is 45?

Answer 1

but u didn't post complete questions

Answer 2

Volume of an object = length(l)*breadth(b)*height(h)

So, to get the volume of an object you have to multiply the length, breadth and height of the object and if the object is a cube then have to multiply the side of the cube three times such as, (side*side*side) or (side)^3. And always the unit should be in cubic form or unit^3

Here, in your question, by multiplying the dimensions of the object the product becomes 45.