Question

How do I show my work for solving the radius of a circle if the area is 78.5 cm^2

Answer 1

9514 1404 393

Answer:

  radius = 5 cm

Step-by-step explanation:

The point of "show your work" is to have to do exactly that. If you know the answer to the problem, you are being requested to show how you got it. If you got it by using a web calculator, then show your input and its result.

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If you worked the problem yourself, you probably did it by filling in numbers in the equation for the area of a circle:

  A = πr²

  78.5 = 3.14×r²

Dividing both sides by 3.14 gives the square of the radius:

  78.4/3.14 = r² = 25

Taking the positive square root gives the radius:

  r = √25 = 5

The area is in square centimeters, so the radius is in centimeters:

  radius = 5 cm