If the square root of three times a number is 15 how do you find the number?

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Answer 1 · 2015-09-16T22:23:42

If $sqrt(3n) =15$
then $n = 75$

Method 1
$sqrt(3n) =sqrt(3)*sqrt(n)$

$sqrt(3)*sqrt(n) = 15$

$sqrt(n) = 15/sqrt(3)$

$=(15sqrt(3))/3 = 5sqrt(3)$

$n = (5sqrt(3))^2$

$=5^2*(sqrt(3))^2$

$=25*3$

$=75$

Method 2
If $sqrt(3n) =15$

then

$3n = 15^2 = 225$

$n=75$