In the figure, tangents and are drawn to a circle with centre from an external point . If is a tangent to the circle at and = 15 cm, find the perimeter of ΔPCD
We know that the lengths of the two tangents from an exterior point to a circle are equal.
CA = CE, DB = DE and PA = PB.
Now, the perimeter of ΔPCD = PC + CD + DP
= PC + CE + ED + DP
= PC + CA + DB + DP
= PA + PB = 2 PA (PB = PA)
Thus, the perimeter of ΔPCD = 2×15 = 30 cm.