Advertisements
Advertisements
Question
A 7m wide road surrounds a circular garden whose area is 5544m2. Find the area of the road and the cost of tarring it at the rate of Rs.150 per m2.
Advertisements
Solution
we know,
The area of the ring between two concentric circles equals the area of the larger circle minus the area of smaller circle.
Let the radius of the outer and inner ring be R and r respectively.
Here the circular garden is the inner circle and the 7m wide road os the ring area of the ring between two concentric circles = π(R2 - r2)
The Area of a Circle with radius r = πr2
Here,
πr2 = 5544m2
⇒ r = 42
⇒ R = 42 + 7
= 49
inner Circle has radius r
= 42 and outer Circle has radius R
= 49
π(492 - 422)
= `(22)/(7) xx (2401 - 1764)`
= `(22)/(7) xx 637`
= 2002m2
The cost of paying the road at the rate of Rs.150per m2
= 2002 x 150
= Rs.3,00,300.
APPEARS IN
RELATED QUESTIONS
The floor of a rectangular hall is 24 m long and 18 m wide. How many carpets, each of length 2.5 m and breadth 80 cm, will be required to cover the floor of the hall?
A 36-m-long, 15-m-borad verandah is to be paved with stones, each measuring 6dm by 5 dm. How many stones will be required?
Find the area enclosed between two concentric circles of radii 3.5 cm and 7 cm. A third concentric circle is drawn outside the 7 cm circle , such that the area enclosed between it and the 7 cm circle is same as that between the two inner circles . Find the radius of the third circle correct to one decimal place.
A chord PQ of length 12 cm subtends an angle of 120° at the centre of a circle. Find the area of the minor segment cut off by the chord PQ.
In the following figure, the shaded area is
The radius of a circle is 20 cm. It is divided into four parts of equal area by drawing three concentric circles inside it. Then, the radius of the largest of three concentric circles drawn is
Find the area of the major segment APB of a circle of radius 35 cm and ∠AOB = 90°, as shown in the given figure.
The diameters of three circles are in the ratio 3: 5: 6. If the sum of the circumferences of these circles is 308 cm; find the difference between the areas of the largest and the smallest of these circles.
Lalitha wants to buy a round carpet of radius is 63 cm for her hall. Find the area that will be covered by the carpet
The area of the circle is 154 cm2. The radius of the circle is ______.
