Question

If the circumference of a circle is 5cm, then the diameter is ____cm.

a. 5 cm
b. 31.4 cm
c. 15.7 cm
d. 1.57 cm

Answer 1

The diameter of a circle with a circumference of 5 cm is found by dividing the circumference by the value of π (pi), which gives approximately 1.59 cm, making the closest answer 1.57 cm.

Step-by-step explanation:

If the circumference of a circle is 5 cm, then the diameter can be found using the formula for circumference, which is C = πd, where C is the circumference and d is the diameter. We can rearrange this formula to solve for the diameter like so: d = C/π. Plugging in the given circumference (5 cm) and using the approximate value of π (3.14), we get d = 5 cm / 3.14, which gives us approximately 1.59 cm. Therefore, the closest answer to the actual diameter would be:

d. 1.57 cm

Answer 2

Let’s start with the circumference of a circle formula and solve for “d” (diameter):

C=2πr

The circumference, “C,” is 5cm

5=2πr

Let’s rewrite the formula using the commutative property of multiplication so we can solve for “d:”

5=π2r

The order in which numbers are multiplied does not affect the product. Since the diameter is double the radius, 2r will equal the diameter since 2r equals r+r. So, we can substitute “d” in for 2r:

5=πd

Now, let’s solve for d

Divide both sides by pi:

5/π=d

1.591=d

We can check this back into the formula:

C=π(1.591)

C=4.998


So, your answer is 1.57 since it is the closest.