In the figure below, how much more is the perimeter of the larger circle than that of the smaller circle?
Let the radius of the smaller circle be r cm.
∴ Radius of the larger circle = (r + 1) cm
Perimeter of the smaller circle = 2πr cm
Perimeter of the larger circle = 2π(r + 1) cm = (2πr + 2π) cm
Difference between the perimeters of the larger circle and smaller circle
= {(2πr + 2π) − 2πr} cm
= 2π cm
Therefore, perimeter of the larger circle is 2π more than the perimeter of the smaller circle.