Can anyone tell me correctly​

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

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92