Question

What are the properties of $R$ used in the following? $\pi \times 1=\pi$

Answer 1

We know that $1$ is the identity element under multiplication for the real numbers, since if $a$ is any real number then $a\times 1=1\times a=a$

Now, since it is given that $\pi \times 1=\pi$, therefore, $1$ is the identity element.

Hence, the identity element property ofmultiplication is used in $\pi \times 1=\pi$.