A perimeter

The perimeter of a parallelogram is 2.8 meters. The length of one of its sides is equal to one-seventh of the entire perimeter. Find the lengths of the sides of the parallelogram.

Correct answer:

a =  0.4 m
b =  1 m

Step-by-step explanation:

$$\begin{gathered} p=2.8\text{m} \\ a=\frac{1}{7}\cdot p=\frac{1}{7}\cdot 2.8=\frac{2}{5}\text{m}=0.4\text{m} \end{gathered}$$

$$\begin{gathered} p=2(a+b) \\ b=p/2-a=2.8/2-0.4=1\text{m} \end{gathered}$$

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