Tangent to a Circle
Tangent
Tangent
The tangent to a circle (show in red in the diagram) is a line that touches the circle at exactly one point. The tangent is perpendicular to the radius connecting that point to the centre of the circle.
The tangent to a circle (show in red in the diagram) is a line that touches the circle at exactly one point. The tangent is perpendicular to the radius connecting that point to the centre of the circle.
Find the Equation of a Tangent to the Circle at Point A
Find the Equation of a Tangent to the Circle at Point A
Step 1: Find the gradient from the centre of the circle to Point A.
Step 1: Find the gradient from the centre of the circle to Point A.
Step 2: Find the gradient of the tangent using m1m2 = −1.
Step 2: Find the gradient of the tangent using m1m2 = −1.
Step 3: Find the equation of the tangent by substituting the gradient of the tangent (Step 2) and point A.
Step 3: Find the equation of the tangent by substituting the gradient of the tangent (Step 2) and point A.