If the length of a diagonal of a quadrilateral is 10 cm and lengths of the perpendiculars on it from opposite vertices are 4 cm and 6 cm, then area of quadrilateral is

1. 100 cm²

2. 200 cm²

3. 50 cm²

4. None of these.

Area of a rhombus is 90 cm². If the length of one diagonal is 10 cm then the length of other diagonal is

1. 18 cm

2. 9 cm

3. 36 cm

4. 4.5 cm

In the adjoining figure, OABC is a square of side 7 cm. OAC is a quadrant of a circle with O as center. The area of the shaded region is

1. 10.5 cm²

2. 38.5 cm²

3. 49 cm²

4. 11.5 cm²

The adjoining figure shows a rectangle and a semicircle. The perimeter of the shaded region is

1. 70 cm

2. 56 cm

3. 78 cm

4. 46 cm