Answer:
= 8.9 units
Explanation:
When a chord intersects with a tangent outside a circle then we use the relationship;
X ² = AO × BO, Where A and are the points of intersection of the chord an the circle, while O is the point of intersection between the chord and the tangent.
Therefore;
x² = 4 × 20 or 8 × 10
x² = 80
x = √80
= 8.944
≈ 8.9