It looks like rsu might be a right angle is it?
Please help with A and B

Answer:
(b) NO
Step-by-step explanation:
It must have the square to to be a right angle
Answer:
A: It is obtuse
B: It is a right angle
Step-by-step explanation:
A: Angle RST equals 110*, if it is greater than 90*, it is obtuse
B: Right Angles are 90*, so this is simple, you subtract RST by UST, so 110-20=90