Tutorial World Primary 6
Name:_________________________ Date:_______________

Circles (5.1)

A. Solve the problems below. [pi = 3.14 or (22/7)]
1. The radius of a circle is 10 cm. If the radius is increased by 20%, find the percentage increase in area and circumference.

2. The sides of the square is 7 cm long. Comparing the square with the circle, find
(a) the difference in area
(b) the difference in perimeter?

3. If the area of a circle is 154 cm square, what is the circumference? [ pi = (22/7) ]

4. The radius of the hour hand on a clock is 12 cm long. From noon to 3.00 pm, what area of the clock is swept by the hour hand?

5. The diameter of a wheel is 0.1 m. For the wheel to roll over a distance of 9.42 m, how many revolutions will it make? [ pi = 3.14 ]

6. A swimming has the shape of a semi-circle. If the area is 308 square metres, find the perimeter of the pool. [pi=(22/7)]

7. The diameter of the circle is 5 cm. The angle of the shaded portion is 60 degrees. Find the area of the unshaded portion.

8. The radius of the smaller circle is 3.5 cm. The radius of the larger circle is twice that of the smaller circle. Find the area of the shaded portion? [ pi = (22/7) ]

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