Chapter-4: Basic Geometrical Ideas

Exercise 4.5

Q1.​​ Draw a rough sketch of a quadrilateral PQRS. Draw its diagonals. Name them. Is the​​ meeting point of the diagonals in the interior or exterior of the quadrilateral?

Ans.

Diagonal PR and diagonal SQ meet at O, which is inside the quadrilateral.

Q2.​​ Draw a rough sketch of a quadrilateral KLMN. State:

(a) Two pairs of opposite sides.

(b) Two pairs of opposite angles.

(c) Two pairs of adjacent sides.

(d) Two pairs of adjacent angles.

Ans.

Q3.​​ Investigate:

Use strip and 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 quadrilateral?

Ans.