91- 6303239042
Condition for a Line to Be Tangent to a Circle
For circle with centre $$(h,k)$$ and radius $$r$$, and line:
$$ Ax+By+C=0 $$
the line is tangent if:
$$ \frac{|Ah+Bk+C|}{\sqrt{A^2+B^2}}=r $$
Usage
- Used to test whether a given line touches the circle at exactly one point.
