A circle touches all four sides of a quadrilateral ABCD. If AB = 18 cm, BC = 21 cm and AD = 15 cm, then length CD is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 18 cm
Given that
In a cyclic quadrilateral ABCD
If AB = 18 cm, BC = 21 cm and AD = 15 cm,
As we know the property of cyclic quadrilateral ABCD
The sum of parallel sides equal to each other
⇒ AB + CD = BC + AD
⇒ 18 + CD = 21 + 15
⇒ CD = 36 - 18 = 18 cm