Let A be the centre of the circle `x^2+y^2-2x-4y-20=0` Suppose that the tangents at the points B(1,7) and D(4,-2) on the circle meet at the point C. Find the area of the quadrilateral ABCD

Answer

5

Explanation

`AB` is a segment parallel to `y-` axis and therefore tangent at
`B` will be parallel to `x -` axis.
`rArr C = (a, 7)`
Using `DC = BC`, we get `C = (16, 7)`
`rArr BC = 15`
So that Area `(DeltaABC) = (75)/(2)`
`rArr` Area of quadrilateral `= 75`