Question

The diameter of a circular park is 98 m. On its outside, there is a 3.5 m wide road. Find the cost of

constructing the road at Rs.327 per square metre


.​

Answer 1

Answer:

$Rs.365095.5$

Step-by-step explanation:

The Diameter of the Circular Park$(d)$ = $98$ $meters$

⇒The Radius of the Circular Park$(r)$ = $\frac{d}{2}$ = $49$ $meters$

Width of Road$(w)$ = 3.5m

⇒The Radius of the Circular Park including the Road$(R)$ = $r + w$ = $52.5$ $meters$

∴The Area of the Road = Area of Park including Road - Area of Circular Park

Area of Park including Road = $\pi R^{2}$ ; Area of Park = $\pi r^{2}$

⇒Area of The Road$(A)$ = $\pi R^{2} -\pi r^{2}$

⇒$A = \pi (R^{2} -r^{2})$

⇒$A = \pi (2756.25 - 2401)$

⇒$A = \pi (355.25)$

⇒$A = \frac{22}{7} *355.25$

⇒$A = 22*50.75$

⇒$A = 1116.5$ $m^{2}$

Cost of constructing the Road = $Rs.327$ $per$ $m^{2}$

⇒Cost of constructing a $1116.5$ $m^{2}$ Road = $327*1116.5$ = $Rs.365095.5$

Answer 2

Answer:

1825

1825- 1826

William Sturgeon (British) invents the electromagnet, a coil of wires with an iron core to enhance the magnetic field.