Question

Michelle found the area of a circle as 78.5 . She used 3.14 for π. What is the radius of the circle? Explain how you found your answer.

Answer 1

Answer:

$r=5$

Step-by-step explanation:

A circle is a geometric figure consisting of a shape established from a closed curved line. The circle has a main characteristic that is that all the points that are established from its center have the same distance to the line that serves as a perimeter, that is, they are equidistant. The center of the circle is coincident with the center of the circumference. The segment is known as the radius which allows the center to be connected to any point on the perimeter.

The area of a circle of radius $r$ is given by:

$A=\pi r^2$

According to the problem:

$A=78.5\\\pi=3.14$

Using the previous equation, and the data provided, we will be able to find the radius of the circle:

$78.5=3.14r^2$

Solving for $r$:

$r^2=\frac{78.5}{3.14} \\\\r^2=25\\\\r=\sqrt{25} \\\\r=\pm 5$

Since a negative radius wouldn't have any sense. The radius of the circle is:

$r=5$

Answer 2

Answer:

5 units

Step-by-step explanation:

Given:-

- The area of the circle was computed to be A = 78.5

- The value of π is estimated to be = 3.14

Find:-

What is the radius of the circle?

Solution:-

- The area of a circle (A) with radius ( r ) is computed by the following formula:

                            A = π*r^2

- Divide the equation by π :

                            r^2 = ( A / π )

- Take the square root of the entire equation:

                            r = √ ( A / π )

- Substitute the given values:

                           r = √ ( 78.5 / 3.14 )

- Resolve the fraction:

                          r = √25

- The perfect square root of 25

                         r = 5

Answer: The radius of the circle is r = 5 units