Explanation:
The first one is true.
We can see this by converting the problem from radian to degree
![2\pi * ((180)/(\pi) = 360^\cric )](https://img.qammunity.org/2020/formulas/mathematics/college/hbjf62y29t653xwx17pve4qlrja4gopvta.png)
The second one is true.
![\pi * ((180)/(\pi) = 180^\cric )](https://img.qammunity.org/2020/formulas/mathematics/college/c4wtodqjhotr5dx4zlp3oakmuqpb67j9d8.png)
There is 180 degrees in a semi / half circle
(Answer) The third one is not true.
does not equal the arc
The length of an arc equals
![s = r\theta](https://img.qammunity.org/2020/formulas/mathematics/college/jc7svihr960lq335onirtq24mp6wdwl0ul.png)
s = length
r = radius
![\theta = angle\ in\ radians](https://img.qammunity.org/2020/formulas/mathematics/college/2pu79m8tarxdffk7lcjfoqvy5t1gbzg175.png)