Step-by-step explanation:
Area of the circle = 1400π
ie. πr^2 = 1400π . ie r^2 =1400. So r=10√14
Area A = πr^2.Differentiate w.r.t.t
dA/dt = 2πr. dr/dt
900 = 2×π×10√14 .dr/dt
So. dr/dt = 900/2×π×10√14 = 45/π√14 m/sec.
Hope this answer helps you :)
Have a great day
Mark brainliest