Hello there! Thank you for asking your question here at Brainly. I will be assisting you today with how to handle this problem, and will teach you how to handle it on your own in the future.
First, let's evaluate the question.
"The circumference of a circle is 6.28. What is the area of a circle?"
Now, let's remember the different formulas for area and circumference.
The circumference is "2•3.14•r", while the area is "3.14•r•r".
We have our circumference, 6.28.
However, we are looking for the area. Since we have the circumference, we need to narrow down to the radius (so we can solve for the area).
Let's set this up as an equation;
C = 2 • 3.14 • r
Plug in the value for our circumference.
6.28 = 2 • 3.14 • r
Multiply 2 by 3.14 and r to simplify the right side of the equation.
2 • 3.14 • r = 6.28 • r = 6.28r
We're now left with:
6.28 = 6.28r
Divide both sides by 6.28 to solve for r.
6.28 / 6.28 = 1
6.28r / 6.28 = r
We are now left with the radius:
R = 1.
Now, we can solve for the area.
Remember our formula for the area.
A = r • r • 3.14.
Plug in 1 for r.
A = 1 • 1 • 3.14
A = 3.14.
Your area is 3.14 units^2.
I hope this helps, and has prepared you for your future problems in relation to this topic!
Answer:
30
Step-by-step explanation:
I don't know how to explain it sorry but can I still get brainliest please
Answer:

Step-by-step explanation:
Given
Hemisphere

Cone

Required
Determine the radius of the cone
First, we calculate the volume (V1) of the hemisphere.

Substitute 7 for r



Volume (V2) of a cone is:

Because the lead is cast into a cone, then they have the same volume.
So, we have:


Substitute 49 for h

Divide both sides by 49




<em>Hence, the radius of the cone is 3.74cm</em>
Answer:
3.2
Step-by-step explanation:
The correct answer is:
R= c/2(3.14)