Write the equation in standard form for the circle that has a diameter with endpoints (-4, 5) and (-4, -9).
Options
A
B
C
D
Answer & Analysis
Answer
D
Analysis
Question Analysis
The main focus is to find the center and radius of the circle using the endpoints of the diameter and then write the equation of the circle in standard form.
Key Concept Explanation
The standard form of a circle's equation is , where is the center of the circle and is the radius. The center of the circle is the midpoint of the diameter, calculated by the midpoint formula , and the radius is half the length of the diameter, calculated by the distance formula .
Step - by - Step Solution
1. Find the center of the circle:
Given the endpoints of the diameter and .
For the - coordinate of the center, .
For the - coordinate of the center, . So the center of the circle is .
2. Find the radius of the circle:
Use the distance formula to find the length of the diameter between and .
.
The radius , and .
3. Write the equation of the circle:
Substitute , , and into the standard form
Want More Practice Questions?
Access thousands of practice questions with detailed explanations on Scholardog.