Question

How does `sinx=0` equals π?

Answer 1

The sine function equals `0` for every multiple of `pi~~3.14`

graph{sinx [0, 7, -1.2, 1.2]}

`pi` radians is equal to `180^0`

The sine-function goes from `0` to `1` at `90^0=pi//2`
And then back to `0` at `180^0=pi`
Down to `-1` at `270^0=3pi//2`
And up to `0` again at `360^0=2pi`

So it will be `0` at every multiple of `pi`

Summary
`sin x=0 ->x=k*pi`, with `k` any whole number