Question

Write the equation of the circumference that meets the condition: Center on the line: x -4y = 1 And it passes through the points A (3,7) and B (5,5)

Answer 1

Answer:

(x + 3)² + (y + 1)² = 100

Step-by-step explanation:

Equation of a circle is:

(x − h)² + (y − k)² = r²

where (h, k) is the center of the circle and r is the radius.

The center is on the line x − 4y = 1, so:

h − 4k = 1

h = 1 + 4k

(x − 1 − 4k)² + (y − k)² = r²

Two points on the line are (3, 7) and (5, 5), so:

(3 − 1 − 4k)² + (7 − k)² = r²

(5 − 1 − 4k)² + (5 − k)² = r²

Set the equations equal:

(3 − 1 − 4k)² + (7 − k)² = (5 − 1 − 4k)² + (5 − k)²

(2 − 4k)² + (7 − k)² = (4 − 4k)² + (5 − k)²

4 − 16k + 16k² + 49 − 14k + k² = 16 − 32k + 16k² + 25 − 10k + k²

4 − 16k + 49 − 14k = 16 − 32k + 25 − 10k

53 − 30k = 41 − 42k

12k = -12

k = -1

h = 1 + 4k

h = -3

(3 − 1 − 4k)² + (7 − k)² = r²

(3 − 1 + 4)² + (7 + 1)² = r²

6² + 8² = r²

r = 10

Therefore, the equation of the circle is:

(x + 3)² + (y + 1)² = 10²