Question

1. For each of the following closed cylinders,
find (i) its volume, (ii) its total surface area.
(a)
7 cm
12 cm
(b)
1.2 m
4 m
(c)
15 mm
63 mm​

Answer 1

Answer:

$\huge\mathfrak\red{question}$

for each of the following closed cylinders find

• it's volume.
• it's total surface area.

figure (a)

• radius= 7cm
• height=12cm

figure (b)

• diameter=1.2m
• height= 4m

figure (c)

• radius=15mm
• height=63mm

$\huge\underline\mathfrak\blue{solution:-}$

$\orange{finding\:figure\:\:(a)}$

$\pink{find\:volume}$

using formula:-

πr²h

$= \frac{22}{7} \times 7 \times 7 \times 12$

$= 22 \times 7 \times 12$

$= 154 \times 12$

$= 1848cm$

$\green{finding\:total\:surface\:area}$

$\blue{using\:formula:-}$

2πr(r+h)

$= 2 \times \frac{22}{7} \times 7(7 + 12)$

$= \: 2\times 22 \times(7 + 12)$

$= \: 44 \times 19$

$= \: 836 {cm}^{2}$

$\orange{finding\:figure\:(b)}$

$\pink{find\:volume}$

$\blue{using\:formula:-}$

πr²h

find radius

$radius = \frac{d}{2}$

$radius = \frac{1.2}{2}$

$radius = 0.6m$

$\pink{find\:volume}$

$= \frac{22}{7} \times 0.6 \times 0.6 \times 4$

$= \frac{22}{7} \times 0.36 \times 4$

$= \frac{22}{7} \times 1.44$

$= 4.52m$

$\green{find total surface area}$

$\blue{using formula:-}$

= 2πr(r+h)

$= \: 2 \times \frac{22}{7} \times 0.6(0.6 + 4)$

$= \: 2 \times \frac{22}{7} \times 0.6(4.6)$

$= \: 2 \times \frac{22}{7} \times 2.76$

$= \: 17.34 {m}^{2}$

$\orange{finding figure (c)}$

$\pink{find volume}$

$\blue{using formula:-}$

πr²h

$= \: \frac{22}{7} \times 15 \times 15 \times 63$

$= 22 \times 225 \times 9$

$= \: 22 \times 2025$

$= \: 44550 \: {mm}^{2}$

$\green{finding total surface area}$

$\blue{using formula:-}$

2πr (r+h)

$= 2 \times \frac{22}{7} \times 15(15 + 63)$

$= 2 \times \frac{22}{7} \times 15(78)$

$= 7354.28 \: {mm}^{2}$

Answer 2

it will help you

have a nice day