If a circle circumscribes a rectangle with side 4 cm and 3 cm, then find the difference between the area of the circle and rectangle?
1). 19.625 cm2
2). 12.625 cm2
3). 7.625 cm2
4). 10.625 cm2
Solution:
Given : A circle circumscribes a rectangle with,
Length 'l' = 4 cm and Breadth 'b' = 3 cm.
To find : Difference between the area of the circle and rectangle.
Area of rectangle = Length × Breadth
= 4 × 3 = 12 cm²
To find the area of the circle we have to find the diagonal of the rectangle which gives us the diameter of the circle.
To find the diagonal we have to use Pythagoras Theorem.
Diagonal (d) = √( l² + b² )
d = √( 4² + 3² )
d = √( 16 + 9 )
d = √( 25 )
d = 5 cm
We know that,diagonal of rectangle = diameter of circle
Diameter (D) = 5cm
Radius (r) = 5/2 = 2.5 cm
Area of the circle = πr² cm²
Area of the circle = 3.14 × 2.5 × 2.5 cm²
Area of the circle = 19.625 cm²
Difference between the two areas = (19.625 - 12)cm² = 7.625 cm²
So, the correct option is 3). 7.625 cm²