Explanation
For alternate angles between parallel lines:
[tex]\angle SOP=\angle RQP=x[/tex]
Let's name this measure x
The measure of the arc SP is x and the measure of the arc PR is twice x, we have:
Then the measure of the arc RS is also x. We have:
[tex]arc(SP)=arc(SR)=x[/tex]
Since the arcs have the same measure, we can state that:
[tex]\bar{SP}=\bar{SR}[/tex]
