In △OPQ, ∠OPQ=90∘. A circle is drawn with centre O and radius OP.
a. (i) Show that the point P lies on the circle.
b. (ii) Prove that the point Q lies on the tangent to the circle at P.
c. (iii) If OP=6 cm and OQ=10 cm, calculate the length of the tangent segment from Q to the circle.