Answer:
i think it would be number 3.
Hope this helps.
Step-by-step explanation:
Answer:
18 but look at others awnsers aswell
Step-by-step explanation:
Answer:
its probably is B. I am not sure. I wouldnt trust me though but you can if you want. ._.

We know that, in ∆ABC,
∠A+∠B+∠C = 180°
But the triangle is right angled at C
ie., ∠C = 90°
Therefore, ∠A+∠B+ 90° = 180°
⇒ ∠A + ∠B = 90°
Therefore, <u>cos(A + B) = cos 90º = 0</u>