question_answer

The length of the two adjacent sides of a rectangle inscribed in a circle are 3 cm and 4 cm respectively. Then the radius of the circle will be

A)  6 cm                           

B)  2.5 cm

C)  8 cm                           

D)  8.5 cm

Correct Answer: B

Solution :

(b): Diameter of a circle = Diagonal of rectangle \[BC=4cm,\,CD=3cm.\] \[\therefore \]\[BD=\sqrt{B{{C}^{2}}+C{{D}^{2}}}=\sqrt{{{4}^{2}}+{{3}^{2}}}=\sqrt{16+9}\] \[=\sqrt{25}=5\]cm. \[\therefore \] Radius of a circle=\[BO=\frac{BD}{2}=\frac{5}{2}=2.5\]cm.