A quadrilateral ABCD has a circle inscribed within it. Given that the lengths of sides AB, BC, and CD are 6 cm, 7 cm, and 8 cm respectively, what is the length of side AD?
Show answer & explanation
Correct answer: C
Explanation
If a circle is inscribed within a quadrilateral (tangential quadrilateral), then
the sums of the opposite sides are equal.
AB + CD = BC + AD
6 + 8 = 7 + AD
14 = 7 + AD
AD = 7 cm