Advertisements
Advertisements
Question
If radius of a circle is increased to twice its original length, how much will the area of the circle increase?
Options
1.4 times
2 times
3 times
4 times
Advertisements
Solution
4 times
Explanation:
Let r be the radius of the circle.
∴ Area of circle = π2
If radius is increased to twice its original length, then radius will be 2r.
Now, area of new circle = π(2r)2 = 4π2 = 4 times of original area
Hence, the area of circle will be increased by 4 times.
APPEARS IN
RELATED QUESTIONS
A rectangular park 358 m long and 18 m wide is to be covered with grass, leaving 2.5 m uncovered all around it. Find the area to be laid with grass.
From a circular piece of cardboard of radius 3 cm two sectors of 900 have been cutoff . Find the perimeter of the remaining portion nearest hundredth centimeters ( `"Take" pi = 22/ 7`).
In the following figure, ABCD is a rectangle, having AB = 20 cm and BC = 14 cm. Two sectors of 180° have been cut off. Calculate:
the length of the boundary of the shaded region.
In the following figure, the square ABCD is divided into five equal parts, all having same area. The central part is circular and the ines AE, GC, BF and HD lie along the diagonals AC and BD of the square. If AB = 22 cm, find:
the circumference of the central part.
In the given figure, the side of square is 28 cm and radius of each circle is half of the length of the side of the square where O and O' are centres of the circles. Find the area of shaded region.
What is the length (in terms of π) of the arc that subtends an angle of 36° at the centre of a circle of radius 5 cm?
How many revolutions a circular wheel of radius r metres makes in covering a distance of s metres?
The area of a circle is 220 cm2. The area of ta square inscribed in it is
Find the area of a flat circular ring formed by two concentric circles (circles with the same centre) whose radii are 9 cm and 5 cm.
The floor of the circular swimming pool whose radius is 7 m has to be cemented at the rate of ₹ 18 per m2. Find the total cost of cementing the floor
