Question

A cistern $6$ m long and $4$ m wide contains water to a depth of $1.25$ m. What is the area of wetted surface?

• A. $40$ sq. m
• B. $45$ sq. m
• C. $49$ sq. m
• D. $73$ sq. m

Answer 1

The correct option is D $73$ sq. m

Given, $l=6,b=4$

Also given depth i.e., $h=1.25$
Area of the wetted surface $=2[lb+bh+hl]$

$=2\left[\right(6\times 4)+(4\times 1.25)+(1.25\times 6\left)\right]$

$=2[24+5+7.5]$
$=73$ sq. m

Therefore, the area of wetted surface is $73$ sq. m.