Level 3
This figure is not drawn to scale. Wheel A and Wheel B are touching a vertical plastic sheet. The ratio of the radius of the small wheel A to the radius of the big wheel B is 2 : 5. The total radii of Wheel A and Wheel B is 196 cm. Both wheels are rolled out in opposite direction shown until they are 2660 cm apart. The two wheels need to make the same number of revolutions. How many revolutions does each wheel make assuming that each wheel must make a complete revolution? (Take π = 227)
5 m
Level 3
The figure is made up of a right-angled triangle ABC and two semicircles with AB and BC as their diameters respectively. The two semicircles and the line AC meet at D as shown. AB = 12 cm. BC = 16 cm and AC = 20 cm. (Take π = 3.14)
  1. Find the perimeter of the shaded region. Correct the answer to 2 decimal places.
  2. Find the area of the shaded region.
5 m