Question

a rectangular garden measures 5m by 7m. both dimensions are to be extended by the same amount so that the area of the garden is doubled . by how much should the dimensions increase, to the nearest tenth of a metre?

Answer 1

You have 5 * 7= 35
and you want to multiply each side by the same number in order to get double area (70)
so (5*a) * (7*a) = 70
where a is the number you want to multiply
\[35a^2=70\]
\[a^2=2\]
\[a=\sqrt{2}\]