Solution:
Two tangents are drawn to a circle from an external point then they subtend equal angles at the center.Join AD and AE.
In and ,
(Length of the tangents drawn from external point of the circle is equal.) (common side)
(radius of circle)
Hence, (SSS congruency)
By CPCT,
Hence, two tangents are drawn to a circle from as external point then they subtend equal angles at the centre.