Question

The radius and the height of a cylinder are 28 cm and 54.5 cm respectively. It is closed at one end by a hemisphere and at other end by a 21 cm high cone. Find the total surface area of the combined article.

Try to explain by figure in your notebook.​

Answer 1

Given Radius of cylinder = 28cm

Radius of cone and hemisphere attached to it = 28cm

Height of cylinder = 54.5cm

Height of cone = 21cm

Slant height of cone, l =

${l}^{2} = {r}^{2} + {h}^{2} \\ \\ {l}^{2} = {28}^{2} + {21}^{2} \\ \\ {l}^{2} = 784 + 441 \\ \\ {l}^{2} = 1225 \\ \\ l = \sqrt{1225} \\ \\ l = 35cm$

Total Surface area of the article = CSA of cylinder + CSA of hemisphere + CSA of cone

=> 2πrh + 2πr^2 + πrl

= πr(2h + 2r + l)

=

$\frac{22}{7} \times 28(2 \times 54.5 + 2 \times 28 + 35) \\ \\ 22 \times 4(109 + 56 + 35) \\ \\ 22 \times 4 \times 200 \\ \\ 17600cm {}^{2}$

Answer 2

Step-by-step explanation:

find the answer in attached photo