Question

A circular fountain of $5$ m radius lies alone in the centre of a circular park of $700$ m radius. Calculate the total walking area available to pedestrians visiting the park.

• A. $1,738,981.5m^2$
• B. $1,538,521.5m^2$
• C. $1,734,521.5m^2$
• D. none of these

Answer 1

The correct option is B $1,538,521.5m^2$

First concentric circles have commen centre.

Here in this Question inner circle is the circular fountain and outer circle is the circular park and D is the pedestrains.

Here in figure ,

R is the radius of outer circle and r is the radius of inner circle.

$R=700m$ and $r=5m$

formula of area = $\pi .{radius}^2$

So,

Area of inner circle $A_1=\pi r2=\pi 5^2$

Area of outer circle $A_2=\pi R^2={700}^2$

Area between the two circle = $A_2-A_1$=$\pi ({700}^2-5^2)$

Area available to pedestrains=$1538521.5m^2$ =

therefore option B is the answer.