A circle is inscribed in the quadrilateral ABCD, AB = 7, BC = 12, and CD = 9. Find the fourth side of the quadrilateral.

univerkov | August 16, 2021 | education

If a circle is inscribed in a quadrilateral ABCD, then the sums of the lengths of the opposite sides of this quadrilateral are equal.

AB + CD = BC + AD, then AD = AB + CD – BC = 7 + 9 – 12 = 4 cm.

Answer: The length of the fourth side is 6 cm.

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