Question
Find the side $ b $ of a rectangle if side $a = 12\, \text{cm}$ and diagonal $d = 15\, \text{cm}$.
Answer
$9\, \text{cm}$
Explanation
To find side $ b $ use Pythagorean Theorem:
$$ a^2 + b^2 = d^2 $$After substituting $a = 12\, \text{cm}$ and $d = 15\, \text{cm}$ we have:
$$ \left( 12\, \text{cm} \right)^{2} + b^2 = \left( 15\, \text{cm} \right)^{2} $$ $$ b^2 = \left( 15\, \text{cm} \right)^{2} - \left( 12\, \text{cm} \right)^{2} $$ $$ b^2 = 225\, \text{cm}^2 - 144\, \text{cm}^2 $$ $$ b^2 = 81\, \text{cm}^2 $$ $$ b = \sqrt{ 81\, \text{cm}^2 } $$$$ b = 9\, \text{cm} $$This page was created using
Rectangle Calculator