Question

solve the following question from surface area and volume will mark as brainliest. ASAP!

Answer 1

hey mate here is your answer
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Answer 2

$\textbf{\underline{Question:}}$ A well of diameter 4 m with depth if 14 m. The earth taken out is spread evenly around the well to form embankment of 40 cm high. Find width of embankment.

$\Longrightarrow{\boxed{\bold{Answer:10\:m}}}$

$\textbf{\underline{Step-by-step explanation :-}}$

$\textbf{\textit{Since we know that,}}$

Volume of cylinder = πr²h

= 22/7 × (4/2)² × 14 m³

= 176 m³

Now area of embankment

= π( R² - r² )

$\textsf{\underline{Since width is unknown so let it be x.}}$

= 22/7 ( OA² - OB² )

= 22/7 [ ( x + 2 )² - 2² ]

= 22/7 ( x² + 4 + 4x - 4 )

= 22/7 ( x² + 4x )

Now,

$\bold{Area\:of\:embankment}$ × $\bold{height}$ = $\bold{Volume}$

22/7 ( x² + 4x ) × 40/100 m = 176 m³

22/7 ( x² + 4x ) = 176 × 100/40

22/7 ( x² + 4x ) = 440

( x² + 4x ) = 440 × 7/22

x² + 4x = 140

x² + 4x - 140 = 0

x² + 14x - 10x - 140 = 0

x( x + 14 ) - 10( x + 14 ) = 0

( x + 14 )( x - 10 ) = 0

$\textsf{Each getting zero therefore,}$

x + 14 = 0 and x - 10 = 0

x = - 14 m or + 10 m

$\underline{\textbf{Since width can't be negative}}$ $\underline{\textbf{therefore width is 10 m.}}$