Question

Radius of circular base of an ear of corn is 6.6 cm and its length is
11.2 cm. If on an average 1 sqcm area contains 2 corn kernels, find the
total number of kernels on a corn.

Answer 1

r = 6.6 cm
length of corn = h = 11.2 cm
`l^2 = h^2 + r^2`
`l^2 = (11.2)^2 + (6.6)^2`
`l^2` = 125.44 + 43.56
`l^2` = 169
l = 13
Curved surface area of cone shaped corn = πrl

                                             = 3.14 × 6.6 × 13
                                             = 269.412 cm2
Number of kernels = curved surface area × 2
                               = 269.412 × 2
                               = 538.824
∴ average no. of kernels on the corn = 539.