Respuesta :

As OP bisects ∠AOR, ∠AOP = ∠POR = 55°

So, ∠AOR = ∠AOP + ∠POR = 55° + 55° = 110°

As OS bisects ∠ROB, ∠ROS = ∠SOB = x

As total angle on a line is 180°,

110° + x + x = 180°

=> 2x = 70

=> x = 35°

∠POS = ∠POR + ∠ROS = 55° + x = 55° + 35°

=> ∠POS = 90°
It is E because you should multiply 55 by 2