Question

the length, breadth and height of a room are 5m ,6m and 8m respectively. Find the cost of whitewashing the walls and the ceiling at the rate of Rs. 15 per Metre square . use herons formula by finding semi perimetre.
$\sqrt{s(s - a)(s - b)(s - c)}$
S Means semi perimetre

Answer 1

you take 5,6,8 and 15 per meter squre and use formula

Answer 2

Length =5m
Breadth =6m
Height=8m
Total cost= csa + top area*rate
Csa + top area=2h(l+b) +lb
=2*8(5+6)+5*6
=206
Total cost=206*15
=3090 ans