Question

Question 7(i)
If each edge of a cube is doubled
How many times will its surface area increase?

Answer 1

Let the edge of cube be l
Since, Surface are of the cube (A) = $6l^2$
When edge of cube is doubled, then
Surface are of the cube $\left(A^{\prime }\right)=6(2l{)}^2=6\times 4l^2=4\times 6l^2$
$A^{\prime }=4\times A$
increase = A' - A
Hence surface area will increase 3 times