Question

2. Which one of the following is rational?
(a) Area of a circle with radius
1/π
(b) Radius of circle with area
T
1\π
(c) Circumference of circle with radius
1\π
d) Radius of circle with circumference
T
1\π
​

Answer 1

Answer:

When we measure a length with a scale or any other device, we only get an approximate rational value.

Therefore we may not realise that c or d is irrational.

Circumference c or the perimeter of a circle is given by 2πr,

where r is the radius of the circle

π is approximated as 3.14 or

7

22

Also diameter(longest chord of circle) of the circle is equal to 2r.

Hence, c=(2πr),d=2r⇒

d

c

=π

This is analogous to the approximated value of

7

22

which though looks like a rational number of the form

q

p

(q!=0)

But when computed corresponds to a real value of ~3.14.

And real numbers consists of irrational numbers.

Hence, there is no contradiction in the equation =

d

c

.

mark as brainest

Answer 2

Area of circle with radius