Diameter 82242

Around the circular pool with a diameter of 5.5 m is a circular wooden terrace with a width of 130 cm. What is the area size of this terrace?

Correct answer:

S =  27.7717 m²

Step-by-step explanation:

$$\begin{gathered} d=5.5\text{m} \\ x=130\text{cm}\to \text{m}=130:100\text{m}=1.3\text{m} \\ {r}_1=d/2=5.5/2=\frac{11}{4}=2.75\text{m} \\ {r}_2=r_1+x=2.75+1.3=\frac{81}{20}=4.05\text{m} \\ {S}_1=\pi \cdot r_1^2=3.1416\cdot 2.75^2\doteq 23.7583{\text{m}}^2 \\ {S}_2=\pi \cdot r_2^2=3.1416\cdot 4.05^2\doteq 51.53{\text{m}}^2 \\ S=S_2-S_1=51.53-23.7583=27.7717{\text{m}}^2 \end{gathered}$$

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