If d is the diameter of a circle, then its area is

1. πd²

2. $\dfrac{πd^2}{2}$

3. $\dfrac{πd^2}{4}$

4. 2πd²

If the area of trapezium is 64 cm² and the distance between parallel sides is 8 cm, then sum of its parallel sides is

1. 8 cm

2. 4 cm

3. 32 cm

4. 16 cm

If the lengths of diagonals of a rhombus is doubled, then area of rhombus will be

1. doubled

2. tripled

3. four times

4. remains same

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.