Four circles of equal radii are centred at the four vertices of a square. These 4 circles touch a fifth circle of equal radius placed inside the square. The ratio of the shaded area of the circles to the unshaded area of the circles is
A. 1 : 3
B. 2 : 3
C. 3 : 4
D. 2 : 5
Answer:B
Four circles of equal radii are centred at the four vertices of a square. These 4 circles touch a fifth circle of equal radius placed inside the square. The ratio of the shaded area of the circles to the unshaded area of the circles is
A. 1 : 3 B. 2 : 3 C. 3 : 4 D. 2 : 5