If the base is k+7 and the perimeter is 4k+20, what's the height and area of the rectangle?

Sep 24, 2015

Have a look:

Explanation:

$2 x + 2 k + 14 = 4 k + 20$
$2 x = 2 k + 6$
$x = k + 3$
$A = b a s e \times h e i g h t = \left(k + 7\right) \left(k + 3\right) = {k}^{2} + 3 k + 7 k + 21 = {k}^{2} + 10 k + 21$