If a set of m paralled lines intersect another set of n parallel lines (not parallelto the
lines in the first set), then find the number of parallelograms fromed in this lattice structure.

If 5 parallel lines intersect another set of 4 , parallel lines (not parallel to the lines in the first set) then the no. of parallelograms formed in this lattice structure is:

The numbe rof parallelogram formed if 5 parallel lines intersect with 4 other parallel lines is:

The number of parallelograms that can be formed from a set of four parallel lines intersecting another set of three parallel lines.

The S.D for the set of the first 'n' natural numbers is

If there are six straight lines in a plane, no two of which are parallel and no three of which pass through the same point, then find the number of points in which these lines intersect.

Consider the equation y-y_1=m(x-x_1) . If ma n dx_1 are fixed and different lines are drawn for different values of y_1, then (a)the lines will pass through a fixed point (b)there will be a set of parallel lines (c)all the lines intersect the line x=x_1 (d)all the lines will be parallel to the line y=x_1