9. If three cubic biscuits having edges 0.3 m, 0.4 m
1. and 0.5 m respectively are melted and formed into
a single cubic biscuit, then what is the total surface
area of the cubic biscuit?
(a) 1.08 sq m (6) 1.56 sq m
(c) 1.84 sq m (d) 2.16 sqm
Answers
Answer:
Ans is( d) 2.16cm²
Step-by-step explanation:
We have three cubic biscuit whose edges are 0.3 cm,0.4cm ,0.5cm ,we have To find total surface area of new biscuit which is formed by melting three old biscuit
Volume of cube =(edge)³
Volume of first biscuit = (0.3)³=.027cm³
Volume of second biscuit
=(0.4)³=0.064cm³
Volume of third biscuit=(0.6)³=0.216cm³
Let edge of new biscuit be x cm
Volume of new biscuit =x³
Volume of new biscuit =sum of volume of thre old biscuits
x³ =.027 + .064 + .125=.216
x³=.216
x³=(.6)³
x=.6cm
Edge of new biscuit=0.6cm
Surface area of cube =6(edge)²
Surface area of new biscuit=6(0.6)²
=6(.36)=2.16cm²