Circle and rectangle

The circle describes a rectangle with sides of 11.7 cm and 175 mm. What is its length? Calculate the area of the circle described by this circle.

Correct answer:

x =  66.1333 cm
S =  348.0413 cm²

Step-by-step explanation:

$$\begin{gathered} a=11.7\text{cm} \\ b=175/10=\frac{35}{2}=17.5\text{cm} \\ u=\sqrt{a^2+b^2}=\sqrt{11.7^2+17.5^2}\doteq 21.0509\text{cm} \\ r=u/2=21.0509/2\doteq 10.5254\text{cm} \\ x=2\pi \cdot r=2\cdot 3.1416\cdot 10.5254=66.1333\text{cm} \end{gathered}$$

$S=\pi \cdot r^2=3.1416\cdot 10.5254^2=348.0413{\text{cm}}^2$

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