Question

If the diameter of a circle is 2.80 inches, what is the radius? Responses a) 5.6 inches b) 4.6 inches c) 1.4 inches d) 1.2 inch

Answer 1

The circumference of a circle with radius 2.8 is 17.59(*)

Explanation:

Circumference of a cicle in terms of radius:Circumference = 2·π·r = 2·3.14·2.8 = 17.59(*)In terms of diameter:Circumference = π·d = 3.14·5.6 = 17.58(*)In terms of area:Circumference C = √4·π·A = √4·π·24.63 = 17.59(*)(*) 17.59 inches exactly or limited to de precision of this calculator (13 decimal places).Note: for simplicity, the operations above were rounded to 2 decimal places and π was rounded to 3.14.