[Will mark as brainliest] Can someone help me understand this and help me get the answer?

The intersecting tangents theorem says that the measure of angle PQR is half the difference of the measures of the arcs that the tangents intercept. This means[tex]m\angle PQR=\dfrac{m\widehat{PR}_{\rm maj}-m\widehat{PR}_{\rm min}}2[/tex]where [tex]\widehat{PR}_{\rm maj}[/tex] refers to the major arc PR, and [tex]\widehat{PR}_{\rm min}[/tex] refers to the minor arc PR (the one you know has measure [tex](100x)^\circ[/tex]).The major and minor arcs PR form the circle, so their measures add up to 360º:[tex]m\widehat{PR}_{\rm maj}=360^\circ-(100x)^\circ[/tex]Then by the aforementioned theorem, we have[tex](81x-1)^\circ=\dfrac{\left(360^\circ-(100x)^\circ\right)-(100x)^\circ}2[/tex][tex]81x-1=\dfrac{360-200x}2[/tex][tex]81x-1=180-100x[/tex][tex]181x=181[/tex][tex]\implies x=1[/tex]Then the minor arc PR has measure 100º, making the answer A.