1) A figure formed by line segments only is called a polygon .
2) Perimeter of a regular polygon is Number of sides × Measure of each side .
3) Perimeter of a irregular polygon is sum of all sides .
4) Two circles with same centre but different radii is called Concentric circles.
5) Ratio of circumference of circle to its diameter is pie and is named by Greek letter π .
6) Distance around the circle is called circumference.
7) A chord of the circle contains exactly two points on a circle.
8) 1 hectare = 10,000 m²
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