In the given diagram, △ ABC ~ △ PQR and $\dfrac{AD}{PS} = \dfrac{3}{8}$. The value of AB : PQ is :

1. 8 : 3

2. 3 : 5

3. 3 : 8

4. 5 : 8

A right angle triangle shaped piece of hard board is rotated completely about its hypotenuse, as shown in the diagram. The solid so formed is always :

(i) a single cone

(ii) a double cone

Which of the statement is valid ?

1. only (i)

2. only (ii)

3. both (i) and (ii)

4. neither (i) nor (ii)

The three vertices of a scalene triangle are always equidistant from a fixed point. The point is :

1. Orthocenter of the triangle

2. Incenter of the triangle

3. Circumcenter of the triangle

4. Centroid of the triangle

In a circle with radius R, the shortest distance between two parallel tangents is equal to :

1. R

2. 2R

3. 2πR

4. πR