Find the side $ b $ of a rectangle if side $a = 12$ and perimeter $P = 84$.
Answer
$b = 30$
Explanation
To find side $ b $ use formula:
$$ P = 2 a + 2 b $$After substituting $ P = 84 $ and $ a = 12 $ we have:
$$ 84 = 2 \cdot 12 + 2 b $$ $$ 84 = 24 + 2 b $$ $$ 2 b = 84 - 24 $$ $$ 2 b = 60 $$ $$ b = \dfrac{ 60 }{ 2 } $$ $$ b = 30 $$This page was created using
Rectangle Calculator