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*(3.2)^2 \\\end{gathered}`

`\begin{gathered}\\\implies \quad \sf 6* 3.2*3.2 \\\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.