The perimeter of a square is given by $P = 4 \sqrt{A}$ $P=4sqrtA$ where A is the area of the square, determine the perimeter of a square with the area 225?

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Answer 1 · 2017-05-23T12:55:41

$P = 60 units$ $P=60" units"$

Note that $5 \times 5 = 25$ $5xx5=25$ . The last digit of which is 5

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

$5^{2} = 25 \leftarrow Fail$ $5^2=25 color(red)(larr" Fail")$

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

$15^{2} \to 15 (10 + 5) = 150 + 75 = 225 \leftarrow This is the one$ $15^2->15(10+5)=150+75=225color(green)(larr" This is the one")$

Thus we have:

$P = 4 \sqrt{225}$ $P=4sqrt(225)$

$P = 4 \times 15 = 60$ $P=4xx15=60$

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

$P = 60 units$ $P=60" units"$

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