Write the following statement in ‘if-then’ form.

 In an isosceles triangle, the segment joining the vertex and the midpoint of the base is perpendicular to the base.

Write converse of the following statement.

The alternate angles formed by two parallel lines and their transversal are congruent.

Write the converse of the following statement.

If a pair of the interior angles made by a transversal of two lines are supplementary then the lines are parallel.

Write the converse of the following statement.

The diagonals of a rectangle are congruent.

How many midpoints does a segment have?

How many points are there in the intersection of two distinct lines?

How many lines are determined by three distinct points?

Find $d\left(A,B\right)$, if co-ordinates of $A$ and $B$ are $-2$ and $5$, respectively.

If $P-Q-R$ and $d(P,Q)=2, d(P,R)=10$, then find $d(Q,R)$.