Question

2. What is the radius of a circle (rounded to the nearest tenth) that has a circumference of 87 cm?

Answer 1

3.

A = pi x r^2

48 = 3.141... x r^2

÷ by value of pi

15.278... = r^2

Square root the ans, to get r

Thus, R = 3.908..... So, radius is 3.9

2.

Circumference = pi x diameter

87. = 3.141... x d

÷ by value of pi

27.692............. = diameter

Radius is twice the diameter. So, divide diameter by 2 to find the radius.

27.692.....÷ 2 = 13.846...

Thus, radius is 13.8cm

Hope this helps!