1) Given the angles below transform into degrees or radians as needed, round to two decimal points if necessary.

In general, 2pi=360°; then, 4pi radians refer to 2 revolutions around a circumference, as shown in the diagram below
Therefore, 4pi=0°=360°.
Similarly,

720°=0 radians

10°=pi/18 radians.

5pi/8=112.5°.
2) Given that the area of a circle is 30pi and an arc length on it is pi/2; find the central angle generated by such arc in radians, round to three decimal places if needed.
The area of a circle is given by

Then, in our case,

On the other hand, an arc length is given by the formula below

In our case,

The answer is 0.287 radians.