# Precalculus Examples

Find the Circle Using the Diameter End Points
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Step 1
The diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circumference of the circle. The given end points of the diameter are and . The center point of the circle is the center of the diameter, which is the midpoint between and . In this case the midpoint is .
Step 1.1
Use the midpoint formula to find the midpoint of the line segment.
Step 1.2
Substitute in the values for and .
Step 1.3
Step 1.4
Divide by .
Step 1.5
Cancel the common factor of and .
Step 1.5.1
Factor out of .
Step 1.5.2
Factor out of .
Step 1.5.3
Factor out of .
Step 1.5.4
Cancel the common factors.
Step 1.5.4.1
Factor out of .
Step 1.5.4.2
Cancel the common factor.
Step 1.5.4.3
Rewrite the expression.
Step 1.5.4.4
Divide by .
Step 1.6
Step 2
Find the radius for the circle. The radius is any line segment from the center of the circle to any point on its circumference. In this case, is the distance between and .
Step 2.1
Use the distance formula to determine the distance between the two points.
Step 2.2
Substitute the actual values of the points into the distance formula.
Step 2.3
Simplify.
Step 2.3.1
Subtract from .
Step 2.3.2
Raise to the power of .
Step 2.3.3
Subtract from .
Step 2.3.4
Raise to the power of .
Step 2.3.5