Task B-1.3. Two small and two large circles are inscribed in a rectangle as shown in the figure. The radius of the large circles is $10 \mathrm{~cm}$. Calculate the area of the part of the rectangle that is not covered by the circles.

![](https://cdn.mathpix.com/cropped/2024_05_30_6e5f8ba1616e2c4b87f4g-02.jpg?height=244&width=460&top_left_y=423&top_left_x=800)
## Solution.

![](https://cdn.mathpix.com/cropped/2024_05_30_6e5f8ba1616e2c4b87f4g-02.jpg?height=241&width=464&top_left_y=861&top_left_x=798)

(If the student has noticed the right triangle and assigned the corresponding values to the sides)

$r=2.5 \mathrm{~cm}$

$P=40 \cdot 20-2 \cdot 10^{2} \pi-2 \cdot 2.5^{2} \pi=800-212.5 \pi \mathrm{cm}^{2}$.