SA3 marksYear: 2023MediumCBSE Class 10
circlestangentsinscribed-circlequadrilateral
Question
In the given figure, a circle is inscribed in a quadrilateral ABCD in which ∠B=90°. If AD=17 cm, AB=20 cm and DS=3 cm, then find the radius of the circle.

Solution
1
DR=DS=3 cm
∴AR=AD−DR=17−3=14 cm
+1 mark2
⇒AQ=AR=14 cm
∴QB=AB−AQ=20−14=6 cm
+1 mark3
Since QB=OP=r ∴ radius =6 cm
+1 mark