Calculate 5391

Viktor shot darts into a circular target with a radius of 5 cm. Inside the circle is a smaller circle with a radius of 2 cm. Calculate Viktor's chance of hitting a smaller circle in percent.

Correct answer:

p =  16 %

Step-by-step explanation:

$$\begin{gathered} r_1=5\text{cm} \\ {r}_2=2\text{cm} \\ {S}_1=\pi \cdot r_1^2=3.1416\cdot 5^2\doteq 78.5398 \\ {S}_2=\pi \cdot r_2^2=3.1416\cdot 2^2\doteq 12.5664 \\ p=100\cdot S_2/S_1=100\cdot 12.5664/78.5398=16\% \end{gathered}$$

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