Question

A well of diameter 150 cm has a stone parapet around it. if the length of the outer edge of the parapet is 660cm, than find the width of the parapet​

Answer 1

${\huge{\orange{\texttt{Solution}}}}$

Given, the diameter of the well (d) = 150 cm.

Let radius and diameter of the parapet is R and D respectively.

Sine, length of the outer edge of the parapet = 770 cm.

Therefore,

2πR = 770 cm

2R = 770 / π = (770 x 7 )/22 = 245 cm

D = 245 cm.

Now, width of the parapet = ( diameter of parapet - diameter of the well)/2 = (245 - 150 )/2 = ( 95)/2 = 47.5 cm

Hence, width of the parapet is 47.5 cm.

$\huge {\boxed{47.5cm}}$

Answer 2

Given Question :-

A well of diameter 150 cm has a stone parapet around it. if the length of the outer edge of the parapet is 660cm, then find the width of the parapet.

Answer

Given :-

• Diameter of well = 150 cm
• Circumference of outer edge of parapet = 660 cm

To find :-

• Width of parapet

Formula used :-

${{ \boxed{{\bold\purple{Circumference \: of \: {Circle}\: = \:2\pi r}}}}}$

$\begin{gathered}\Large{\bold{\purple{\underline{CaLcUlAtIoN\::}}}} \end{gathered}$

$\begin{gathered}\begin{gathered}\bf Let = \begin{cases} &\bf{r \: be \: the \: radius \: of \: well} \\ &\bf{R \: be \: the \: radius \: of \: Parapet} \end{cases}\end{gathered}\end{gathered}$

$\bf \:  ⟼ \large \red{According \: to \: statement } ✍$

☆ Circumference of outer edge of parapet = 660 cm

$\bf \:  ⟼ 2\pi \: R = 660$

$\bf \:  ⟼ 2 \times \dfrac{22}{7} \times R = 660$

$\bf \:  ⟼ R = 105 \: cm$

$\bf \:  ⟼ Also, \: Diameter \: of \: well = 150 \: cm$

$\bf \:  ⟼ So, radius \: of \: well, \: r = 75 \: cm$

$\bf \:Hence, width \: of \: Parapet = R - r$

$\bf\implies \:width \: of \: Parapet = 105 - 75 = 30 \: cm$