Question

i) ii) ii) iv) v) Slant height of conical corn cob is b) 20.11 cm c) 18.11 cm The formula to find the curved surface area of cone is a) 19.11 cm a) pi * r ^ 2 * h b) πrl Curved surface area of the corn cob is (in cm^ 2 ) c) 2arh d) 21.11 cm d) 2pi * r * (r + h) c) 112.73 d) 102.73 If each 1 cm ^ 3 of the surface of the cob carries an average of four grains then how many grains you would find on the entire cob? a) 132.73 b) 122.73 b) 531 c) 432 The formula to find out the total surface area of cone is a) 532 a) pi * r ^ 2 * h b) pi*r * (1 + r) c) 2trh d) 431 d) 2pi * r * (r + h)​

Answer 1

Answer:

CSA of cone cob = πrl

r=2.1cm,h=20cm

Now, l=

r

2

+h

2

=

(2.1)

2

+(20)

2

l=

404.41

=20.11cm

∴ CSA of corn cab =

7

22

×2.1×20.11=132.73cm

2

Number of grains on 1 cm

2

of the surface corn cob =4

∴ Number of grain on 132.73 cm

2

of the surface of corn cab =132.73×4≈531