Question

what is the area of circle of radius 1 cm​

Answer 1

Answer:

the are of circles is

$54cm \sqrt{1}$

Answer 2

Step-by-step explanation:

will increase by 300%.

Step-by-step explanation:

A circle has a 1 cm. of radius, i.e. 2 cm. is the diameter of the circle.

Now, the area of the circle is given by \pi (Radius)^{2} = \pi r^{2} = \frac{22}{7} \times (1)^{2} = 3.143π(Radius)

2

=πr

2

=

7

22

×(1)

2

=3.143 sq. cm. (Approximate.)

If the diameter of the circle is increased by 100%, then the radius will also increase by 100%.

So, R = r(1 + \frac{100}{100}) = 2r = 2R=r(1+

100

100

)=2r=2 cm will be the increased radius.

Hence, the area of the circle will become \pi (Radius)^{2} = \pi R^{2} = \frac{22}{7} \times (2)^{2} = 3.143 \times 4 = 12.57π(Radius)

2

=πR

2

=

7

22

×(2)

2

=3.143×4=12.57 sq. cm.

Therefore, the area of the circle will increase by percentage \frac{12.57 - 3.143}{3.143} \times 100\% = 300\%

3.143

12.57−3.143

×100%=300% .