We saw that 5 measurement of a quadrilateral can determine a quadrilateral uniquely. Do you think any five measurements of the quadrilateral can do this?

What is the sum of the measures of the angles of a quadrilateral?

What do you mean by the term measurement?

How many measurements are required for the construction of a unique quadrilateral ?

What is the sum of the measures of the angles of a convex quadrilateral? Will this property hold if the quadrilateral is not convex? (Make a non-convex quadrilateral and try!)

Investigate: Use strips nad fasteners to make a triangle and a quadrilateral. Try to push inward at any one vertex of the triangle.Do the same to the quadrilateral. Is the triangle distorted ?Is the quadrilateral distorted?Is the triangle rigid? Why is it that structures like electric towers make use of triangular shapes and not quadrilaterals?

Consider a polygon of sides 'n' which satisfies the equation 3*^(n)P_(4)=^(n-1)P_(5) . Q. Number of quadrilaterals thatn can be formed using the vertices of a polygon of sides 'n' if exactly 1 side of the quadrilateral in common with side of the n-gon, is