1.

The center of a circle is (2a, a – 7). Find the values of a if the circle passes through the point (11, -9) and has diameter 10√2 units.

Answer»

Given,

Diameter of the circle = 10√2 units

So, the radius = 5√2 units

Let the center of a circle be 0(2a, a-7) and the circle passes though the point P (11, -9).

Then, OP is the radius of the circle

OP = 5√2

OP2 = (5√2) = 50

(11- 2a)2 + (-9 – a + 7)2 = 50

121 – 44a + 4a2 + 4 + a2 + 4a = 50

5a2 – 40a + 75 = 0

a2 – 8a + 15 = 0

(a – 5)(a – 3) = 0 [Factorisation method]

So, a = 5 or a = 3



Discussion

No Comment Found

Related InterviewSolutions