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How to write the second question of "Basic Training" in the first volume of sixth grade mathematics 17 Expanding Space?
The radius of the circle is changed to r: then the area of the whole graph should be:

3. The square of14 * r +2r * r = 2826.

The square of (3. 14+2)r = 2826

R squared = 2826/5. 14

Shaded area: rectangular area-semicircle

2r*r-3. 14*r squared /2

= 2r square-1.57r square

= =0.5r squared

=0.5*2826/5. 14

Approximately = 275