2021 · Q20
A circle touches all the four sides of a quadrilateral ABCD. If AB = 9 cm, BC = 8 cm and CD = 12 cm, then what is DA equal to?
Elementary MathematicsCircles
- A14 cm
- B13 cm
- C12 cm
- D11 cm
Explanation
For a quadrilateral circumscribing a circle, sums of opposite sides are equal: AB + CD = BC + DA. So 9 + 12 = 8 + DA, giving DA = 13 cm. Hence option B.