Okey so the area of a circle is taken from the equation πr²
now in the sum they have given information as: area of one small circle is 9π
that means :
area of small circle = πr²
= π3²
= π9
so in the sum they have given us the radius of one circle as 3
from this information we understand that the diameter of one small circle should be = 3 ×2
= 6 (as diameter is twice the radius)
we are given 3 of these circles. that means there are 3 times the diameter measured.
so the diameter of the large circle is = 6×3 = 18
as we calculated, since 18 is the diameter of the large circle, it should be taken ½ for radius.
radius of large circle = 18÷2
= 9
now we know the radius of large circle.
taking the equation 'πr²' to find the area:
area of large circle = πr²
= π9²
= π81
your answer is 81π