In ΔABC, is an altitude and ∠A is right angle. If AB = , BD = 4, then CD =

As we know that,

If an altitude is drawn to hypotenuse of a right angled triangle, then the length of each side other than the hypotenuse is the geometric mean of length of hypotenuse and segment of hypotenuse adjacent to the side.

⇒ AB² = BD.BC

⇒ 20 = 4. BC

⇒ BC = 5

Also, CD = BC – BD

CD = 5 – 4

CD = 1

∴ Option (d) is correct.