Find the side $ a $ of a rectangle if side $b = 20$ and perimeter $P = 70$.
Answer
$a = 15$
Explanation
To find side $ a $ use formula:
$$ P = 2 a + 2 b $$After substituting $ P = 70 $ and $ b = 20 $ we have:
$$ 70 = 2 a + 2 \cdot 20 $$ $$ 70 = 2 a + 40 $$ $$ 2 a = 70 - 40 $$ $$ 2 a = 30 $$ $$ a = \dfrac{ 30 }{ 2 } $$ $$ a = 15 $$This page was created using
Rectangle Calculator