Question

3. The area of metal sheet required to make a closed cylinder of height 1 m and base diameter 140 cm is ------------ sq.m *

Answer 1

Given:

• Height of the cylinder = 1m

• Diameter= 140 cm = 1.4 m .

To find :

• Area of metal sheet .

Solution:

•Area of sheet = Total surface area of cylinder

$\star \boxed{\bold{ \: tsa \: of \: cylinder \: = 2\pi \: r(r + h)} }$

Radius = d/2 = 1.4/2 = 0.7m

$\implies \: 2( \frac{22}{7} )(0.7)(1 + 0.7) \\ \\ \implies \: \frac{44}{7} ( \frac{7}{10} )( \frac{17}{10} ) \\ \\ \implies \: \frac{44 \times 17}{100} \\ \\ \implies \: \frac{748}{100} \\ \\ \implies \: 7.48 {m}^{2}$

Hence ,the area of the sheet required to make a closed cylinder is 7.48m².

Answer 2

area of sheet = 2π r (r+h)

=> Area of sheet = 2 (22/7)0.7(1+0.7)

=> Area of sheet = 44/7(7/10)17/10

=> Area of sheet = 44×17/100

=> AREA OF SHEET = 748/100

=> Area of sheet= 7.48m²