Question

The area of a rectangle is 108m^2 and its diagonal is 15m. Find the perimeter of the rectangle. Please without quadratics.

Answer 1

The perimeter of the rectangle is 42m.

Step-by-step explanation:

To find the perimeter of the rectangle, we need to know the lengths of its sides. From the given information, we know that the area of the rectangle is 108m^2 and its diagonal is 15m. We can use this information to find the lengths of the sides.

Let the length of the rectangle be 'l' and the width be 'w'.
Given, lw = 108 and sqrt(l^2 + w^2) = 15.
Squaring both sides of the second equation, we get l^2 + w^2 = 225.
Since lw = 108, we can solve the quadratic equation l^2 - 108l + 225 = 0 to find l. In this particular case, the quadratic factors as (l - 9)(l - 12) = 0, so l = 9 or l = 12.
Substituting the values of l in the equation lw = 108, we find w = 12 or w = 9.
Since the perimeter is the sum of all the sides, the perimeter of the rectangle is (2l + 2w) = (2 * 9 + 2 * 12) = 42m.

Answer 2

`\text{l-length}\\\text{w-width}\\lw-area\\108\ m^2-area\\d-diagonal\\\\\text{The equation}\ \#1:\\\\lw=108\to l=(108)/(w)\\\\\text{The equation}\ \#2:\\\\\text{Use the Pythagorean theorem:}\\\\l^2+w^2=d^2\to l^2+w^2=15^2\to l^2+w^2=225\\\\\text{Subtitute from}\ \#1\ \text{to}\ \#2:`

`\left((108)/(w)\right)^2+w^2=225\\\\(11,664)/(w^2)+w^2=225\qquad\text{multiply both sides by }\ w^2\\eq0\\\\11,664+w^4=225w^2\qquad\text{subtract}\ 225w^2\ \text{from both sides}\\\\w^4-225w^2+11,664=0\qquad\text{substitute}\ t=w^2 > 0\\\\t^2-225t+11,664=0\\\\\text{use the quadratic formula or solve by factoring}.\\\\t^2-144t-81t+11,664=0\\\\t(t-144)-81(t-144)=0\\\\(t-144)(t-81)=0\iff t-144=0\ or\ t-81=0\\\\\boxed{t=144}\ or\ \boxed{t=81}\to w^2=144\ or\ w^2=81\\\\w=√(144)\ or\ w=√(81)\\\\\boxed{w=12\ m}\ or\ \boxed{w=9\ m}`

`\text{Put the values of}\ w\ \text{to the equation}\ \#1:\\\\l=(108)/(12)\to\boxed{l=9\ m}\ or\ l=(108)/(9)\to\boxed{l=12}\\\\\text{The formula of a perimeter of a rectangle:}\\\\P=2l+2w\\\\P=2(12)+2(9)=24+18=42\\\\Answer:\ \text{The perimeter of the rectangle is equal 42 m}.`