Radius of circle (say PO) = 5 cm
Let AB ∥ CD be two tangents which meets the circle at P and Q respectively. And, O be the center of circle.
Property: The tangent at a point on a circle is at right angles to the radius obtained by joining center and the point of tangency.
By above property, we can say that distance between two parallel tangents of a circle is equal to its diameter.
PQ = 2 × PO
= 2 × 5 cm
= 10 cm
Hence, Distance between tangents = 10 cm