1. Divide a circle into several equal parts, which can be arranged in an approximate (rectangular) shape. The (length) of this figure is equivalent to a circle (half the circumference), and its width is a circle (radius), so the formula for expressing the area of a circle by letters is (s = π r 2).

2. A circle with a diameter of 6DM has an area of (28.26dm^2) and a circumference of (18.84dm).

3. The circumference of a circle is 15.7DM and the area is (19.625 dm 22).

4. Double the radius, double the circumference and double the area of a circle.

Draw a maximum circle in a rectangle 3 cm long and 2 cm wide. The area of this circle is (3.14cm 22).