Saved Bookmarks
| 1. |
: A corn cob (see Fig. 13.17), shaped somewhatlike a cone, has the radius of its broadest end as 2.1 cm andlength (height) as 20 cm. If each 1 cm2 of the surface of thecob carries an average of four grains, find how many grainsyou would find on the entire cob. |
|
Answer» Since the grains of corn are found on the curved surface of the corn cob. Total number of grains on the corn cob = Curved surface area of the corn cob x Number of grains of corn on 1cm^2 Now,find the curved surface area of the corn cob.r = 2.1 cmh = 20 cmLet l be the slant height of the corn cob. Then,l^2 = r^2+ h^2= (2.1)^2 + (20)^2=4.41 + 400=404.41l =20.11 C.S.A. of cone= πrl= 22/7 * 2.1 * 20.11= 132.73 cm^2 We know that, Total no. of grains on the corn cob= 132.73 * 4= 530.92 so, approximately there are 531 grains. |
|