Question

If a rectangular tank is 21cm long, 13cm wide and 18cm high and contains water up to a height of 11cm then total surface area is

Answer 1

$\huge \bf{answer} \div$

GIVEN :

length = 21cm

breadth = 13cm

height = 18cm.

TO FIND THE TOTAL SURFACE AREA :

T.S.A = 2(lb + bh + hl)

= 2(21×13 + 13×18 + 18×21)

= 2( 273 + 234 + 387)

= 2(885)

= 1770 cm^2.

$\boxed{required \: answer = {1770cm}^{2} }$

Answer 2

Answer:

The total surface area of the rectangular tank is calculated to be 1770cm².

When tank filled with water to height 11cm then total surface area is 1294cm².

Step-by-step explanation:

Given that

The rectangular tank has length (l) =21cm

                                       Breadth (b) =13cm

                                        Height (h) =18cm

Total surface area for a rectangular tank  $S=2(lb+bh+hl)$

Put the values of l, h and b in above formula:

        ∴         $S=2[(21)(13)+(13)(18)+(21)(18)]\\ S=2(273+234+387)\\ S=2(885)\\ S=1770cm^{2}$

The surface area of rectangular tank filled with water to height h=11cm

               $S=2(lb+bh+hl)$

Now      $l=21cm, b=13cm$ and $h=11cm$

Then            $S=2[(21)(13)+(13)(11)+(21)(11)]\\ S=2(273+143+231)\\ S=2(647)\\ S=1294cm^{2}$