(2,4)
Step-by-step explanation:
I'm not sure in the slightest but with the formula I learned I think this is correct
Answer:

It's change of subject. :)
Step-by-step explanation:
Not entirely sure, but I believe something like this:
∠1 + ∠2 = 180° since they are a linear pair;
Since ∠1 = ∠2, we can say:
∠1 + ∠1 = 180°
2(∠1) = 180°
∠1 = 90°
And since:
∠1 = ∠2
∠2 = 90°
So the angle between t and s is 90°;
An angle of 90° means t and s are perpendicular (⊥)