Question

The perimeter of a square is given by `P=4sqrtA` where A is the area of the square, determine the perimeter of a square with the area 225?

Answer 1

`P=60" units"`

Explanation:

Note that `5xx5=25`. The last digit of which is 5

So what ever we have to square to get 225 will have 5 as a last digit.

`5^2=25 color(red)(larr" Fail")`

`10 color(red)(rarr" cant use as it does not end in 5")`

`15^2->15(10+5)=150+75=225color(green)(larr" This is the one")`

Thus we have:

`P=4sqrt(225)`

`P=4xx15=60`

but to be mathematically correct we should include the units of measurement. AS these are not given in the question we write:

`P=60" units"`