Page 105 - Start Up Mathematics_6

3. Square: A square is a rectangle in which a pair of
adjacent sides are equal.

4. Rhombus: A rhombus is a parallelogram having a pair of adjacent
sides equal.
5. Trapezium: A quadrilateral having a pair of opposite sides parallel is
called a trapezium.

6. Kite: A quadrilateral having two pairs of adjacent sides equal and
opposite sides unequal is called a kite.
Example 20: Say True or False:

(a) The adjacent sides of a rectangle are equal in length.
(b) All the sides of a parallelogram are of equal length.

(c) The opposite sides of a trapezium are parallel.
Solution: (a) False (b) False (c) False

Example 21: Give reasons for the following:
(a) A square can be thought of as a special rectangle.

(b) A rectangle can be thought of as a special parallelogram.
(c) A square can be thought of as a special rhombus.

(d) A parallelogram can be thought of as a special trapezium.
(e) Square is also a parallelogram.

Solution: (a) A rectangle having all sides equal is a square.
(b) A parallelogram with one right angle becomes a rectangle.

(c) A rhombus with each angle a right angle becomes a square.
(d) A trapezium in which parallel sides are equal becomes a parallelogram.

(e) The opposite sides of a square are parallel therefore it is a parallelogram.

Types of Polygons

We have studied that a polygon is a simple closed figure formed by line segments. A polygon
is said to be regular if all its sides are equal in length and all its angles are equal in measure.
A polygon that is not regular is called irregular. We know about polygons of 3 or 4 sides, i.e.,
triangles and quadrilaterals. We now extend the idea of polygons by classifying them on the basis
of the number of sides.

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