Answer: The answer is (d) It is an irrational number.
Step-by-step explanation: Given formula for circumference of a circle is

where 'd' is the length of the diameter and a rational number.
We are to choose one of the given four options for the circumference 'c' of the circle.
We know that the circumference of a circle with diameter 'd' is given by

Comparing this with the given equation, we get

Now, the product of a rational and an irrational number is again irrational, so 'r × d' will be an irrational number.
Hence, the circumference, c = rd is irrational.
Thus, the correct option is (d) It is an irrational number.
Answer:
Use Math-way or photo-math
Step-by-step explanation:
Use Math-way or photo-math
Answer:
B
Step-by-step explanation:
A square root can‘t be negative so
x -1 ≥ 0
x ≥ 1
We can say that the domain is
[1 ; +oo)