Rectangle 80701

One side of the rectangle has length a=9/5 cm, and the length of side b is 7/10 cm greater than the length of side a.
Calculate the perimeter and area of ​​the rectangle.

Correct answer:

o =  8.6 cm
S =  4.5 cm²

Step-by-step explanation:

$$\begin{gathered} a=9/5=\frac{9}{5}=1.8\text{cm} \\ b=a+\frac{7}{10}=\frac{9}{5}+\frac{7}{10}=\frac{18}{10}+\frac{7}{10}=\frac{18+7}{10}=\frac{25}{10}=\frac{5}{2}=2.5\text{cm} \\ o=2\cdot a+2\cdot b=2\cdot \frac{9}{5}+2\cdot \frac{5}{2}=\frac{43}{5}\text{cm}=8.6\text{cm} \end{gathered}$$

$S=a\cdot b=\frac{9}{5}\cdot \frac{5}{2}=\frac{9\cdot 5}{5\cdot 2}=\frac{45}{10}=\frac{9}{2}{\text{cm}}^2=4.5{\text{cm}}^2$

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