Question

an open cylindrical tank of depth 1.5 m and radius of base 70 cm is to be made from a metal sheet how much square metre of metal sheet is needed

Answer 1

area of sheet needed = csa of cylinder + area of base
                     
                                   = $2 \pi rh + \pi r^{2}$
                                 $= \pi r(2h+r)$         
                                  $\frac{22}{7} *0.7(2*1.5+0.7)$
                                  =8.14 metre square                    
                                     

Answer 2

Hlo friend.. Cutiepie Here..

Here is ur answer :

Area of metal sheet needed

= Curved surface area of cylinder + area of base.

Radius r of cylinder = 70 cm = 0.7 m

Height h of cylinder = 1.5 m

Curved surface area of cylinder

$= 2\pi rh$

$= 2 \times \frac{22}{7} \times .7 \times 1.5$

$= 2\times \frac{22}{7} \times \frac{7}{10} \times \frac{15}{10}$

$= \frac{2 \times 22 \times 15}{10 \times 10}$

$= \frac{660}{100}$

$= 6.6 \: {m}^{2}$

Area of base

$= \pi{r}^{2}$

$= \frac{22}{7} \times 0.7$ × 0.7

$= \frac{22}{7} \times \frac{7}{10}$ × 7 / 10


= 22 × 7 / 10 × 10


$1.54 \: \: {m}^{2}$

Area of sheet needed = 6.6 + 1.54

= 8.14 m²

HOPE IT HELPS YOU..