Question

Find the area and perimeter of the circles with following: Diameter = 77cm

Answer 1

The radius of a Circle with diameter d is r = `"d"/(2)`
The Area of a Circle with radius r = πr² 

The radius of a Circle with diameter 77 is r

= `(77)/(2)`
= 38.5cm
The Area of a Circle with radius r 
 = π(38.5)²

= `(22)/(7) xx (38.5)^2`
= 4658.5cm2
The Circumference of a Circle with diameter d is  πd
The Circumference of a Circle with diameter 77 is π x 77

= `(22)/(7) xx 77`
= 242cm.