The Total solution for NCERT class 6-12
The rate of change of the area of a circlewith respect to its radius┬аr┬аat┬аr┬а= 6 cm is
(A) 10╧А (B) 12╧А (C) 8╧А (D) 11╧А
The area of a circle (A)┬аwithradius (r) is given by,
Therefore, the rate of change of the areawith respect to its radius┬аr┬аis
тИ┤When┬аr┬а= 6 cm,
Hence, the required rate of change of thearea of a circle is 12╧А cm2/s.
The correct answer is B.