Math help please!!!!!

Question

Find the circumference of each circle, use 3.14 for . Include units and round to the nearest tenth. Show work.

7.The circumference of a circle is 34.54 cm. What is the diameter and radius of the circle? (Show work)

8. What is the circumference of a circle in terms of , if it has a radius of 3.5 in?

(in terms of means do not substitute 3.14 for pi, leave the symbol in the final answer)

Answer 1

Use the equation Circumference (C) = two(2) times pi(π) times the radius (r)

C = 2πr

For the problem 1:

C = 2(3.14)(7.1) = (6.28)(7.1) = 44.588 m

For problem 2:

r = 12/2 = 6

C = 2(3.14)(6) = (6.28)(6) = 37.68 ft

Do the other problems like this. Be careful when it says or shows diameter because the formula calls for radius. To get radius, divide diameter by 2.

For number 7 you must work backwards to get the radius because you know "C" but not "r"

For instance, problem 7:

34.54 = (2)(3.14)(r)

34.54 = (6.28)(r)

34.54/6.28 = r

r = 5.5

d = 2r

d = (2)(5.5)

d = 11

For problem 8, do not use 3.14 for pi, just leave it as "π"

C = 2πr

C = 2π(3.5)

C = 2(3.5)π

C = 7π