#### Find the circumference of the circles with the following radius:

(i) 7 cm

(ii) 21 cm

(iii) 28 mm

(iv) 3.5 cm

**Solution:**

**More Solutions:**

- Then the area of the resulting triangle:
- The circumference of the circle with diameter 28 cm:
- Then the radius of the circle is:
- If the ratio of the radii of two circles is 2:
- The perimeter of a semicircle (including its diameter) of radius 7 cm is:
- Area of a rectangle and the area of a circle are equal.
- Find the area of the trapezium ACDE.