Question

Example 6 : A corn cob (see Fig. 13.17), shaped somewhat
like a cone, has the radius of its broadest end as 2.1 cm and
length (height) as 20 cm. If each 1 cm² of the surface of the
cob carries an average of four grains, find how many grains
you would find on the entire cob.​

Answer 1

Answer:

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Answer 2

We know that grains are on the curved surface Area First we find the area of corn cob which is in the form of a cone.

Curved Surface Area of corn cob = πrl

r = 2.1 cm, h = 20cm

Let slant height be /

We know that

1² =h² + ²

12 = (20)² + (2.1)2