1.

If the area of the circle `4x^(2)+4y^(2)-8x+16y+k=0` is `9pi` square units, then the value of k isA. 4B. 16C. -16D. `+-16`

Answer» Correct Answer - C
We have,
`4x^(2)+4y^(2)-8x+16y+k=0 rArr x^(2)+y^(2)-2x+4y+(k)/(4)=0`
The radius of this circle is `sqrt(1+4-(k)/(4))=(sqrt(20-k))/(2)`
We have,
Area of the circle `= 9 pi rArr k = -16`


Discussion

No Comment Found

Related InterviewSolutions