If the radii of circles A and B are in the ratio of 1.5:1, then the area of the circles A and B will be in the ratio of -

Explanation

Let the radius of circles A and B are $1.5x$ and $x$ respectively. Area of circle = $\pi \times (radius)^2$ $\because$ Area of circle A : Area of circle B = $\pi (1.5x)^2 : \pi (x)^2$ = $2.25 x^2 : x^2$ = 2.25 : 1 Note - If the ratio of radius or circumference of two circles are $x : y$ then the ratio of their areas will be $x^2 : y^2$. Ratio of area of circle A and B = $(1.5)^2 : (1)^2 = 2.25 : 1 = 9 : 4$ ## Page 21