ABC26GN4294 · Area

Let the original radius of the circle be r. Then, original circumference = 2pr.  105   21  New circumference = 105% of (2pr) =  × 2 πr  = 2 π  r  .  100   20  21 \ New radius = r. 20 2  21  441 2 New area = π ×  r  = πr .  20  400  441 2  41 Increase in area =  πr – πr 2  = πr 2 .  400  400  41 2 1  Increase % in area =  πr × 2 × 100  % = 10.25%.  400 πr 