Question

Find the cost of painting a cubical block of side length 3.2 cm, if painting costs $5 per cm2.

Answer 1

Answer:-

$\longrightarrow \sf \ \: 307.2$

Solution:-

Since painting is done on outer surface of cubical block we will have to find its surface area which is given by-

$\green{ \underline { \boxed{ \sf{Surface \: area \:of \:Cube = 6a^2}}}}$

• where a is side of the cube

$\begin{gathered}\\\quad \sf Surface \: area \:of \:Cube = 6\times(3.2)^2 \\\end{gathered}$

$\begin{gathered}\\\implies \quad \sf 6\times 3.2\times3.2 \\\end{gathered}$

$\begin{gathered}\\\implies \quad \sf 61.44 cm^2 \\\end{gathered}$

Now,

$\maltese \sf Cost \:of \:painting \: 1 \: cm² = \ 5$

$\sf Cost \: of \: painting \: 61.44 \:cm²=61.44×5$

$\sf\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad=\ 307.2$

$\leadsto$Thus it would cost $ 307.2 to paint the entire cubical block.