What is wrong with this circle's area problem?

Question

My solution and my book's solution don't match.

Is something wrong with the my solution?
If so, where and why?

My book says:

The radius r of a circle increases by 50%.
In terms of r, what is the area of the circle
with the increased radius?

My solution:

1. A = $\pi r^2\ $ => Area of any circle
2. ir = $\ 3r/2 \ $ => Increased radio
3. A$\ _{ir} = \pi ir^{2} \ $ => Area of circle with increased radio
4. A$\ _{ir} = \pi (3r/2 )^{2} \ $ => Substituting ir with its value
5. A$\ _{ir} = \pi (9r^2/4 ) \ $ => Square
6. A$\ _{ir} = \ (9\pi r^2 )/4 \ $ => Result

Is the In terms of r tricky?

Answer 1

There is nothing wrong with your answer!