In the diagram below, the line $ST$ST is tangent to circle $\bigodot O$⊙O at the point$T$T.
Find the value of $a$a.
In the diagram below, the line $ST$ST is tangent to circle $\bigodot O$⊙O at the point$T$T.
In the diagram below, $\overline{AX}$AX and $\overline{BX}$BX are tangent to the circle $\bigodot O$⊙O at $A$A and $B$B respectively.
In the diagram below, $\overline{PX}$PX and $\overline{QX}$QX are tangent to the circle $\bigodot O$⊙O at $P$P and $Q$Q respectively.