Question
Find the perimeter $ P $ of a rectangle if side $a = 7\, \text{cm}$ and area $A = 42\, \text{cm}$.
Answer
$26\, \text{cm}$
Explanation
STEP 1: find side $ b $
To find side $ b $ use formula:
$$ A = a \cdot b $$After substituting $A = 42\, \text{cm}$ and $a = 7\, \text{cm}$ we have:
$$ 42\, \text{cm} = 7\, \text{cm} \cdot b $$$$ b = \dfrac{ 42\, \text{cm} }{ 7\, \text{cm} } $$$$ b = 6 $$STEP 2: find perimeter $ P $
To find perimeter $ P $ use formula:
$$ P = 2 a + 2 b $$After substituting $a = 7\, \text{cm}$ and $b = 6\, \text{cm}^0$ we have:
$$ P = 2 \cdot 7\, \text{cm} + 2 \cdot 6 $$ $$ P = 14\, \text{cm} + 12 $$ $$ P = 26\, \text{cm} $$This page was created using
Rectangle Calculator