URGENT CASE, need help please, Trigonometric Functions

Answer:
[tex]\displaystyle 3,8 ≈ AC[/tex]
Step-by-step explanation:
[tex]\displaystyle \frac{4}{AC} = csc\:70 \hookrightarrow ACcsc\:70 = 4 \hookrightarrow \frac{4}{csc\:70} = AC \hookrightarrow 3,7587704831... = AC \\ \\ 3,8 \approx AC[/tex]
OR
[tex]\displaystyle \frac{AC}{4} = sin\:70 \hookrightarrow 4sin\:70 = AC \hookrightarrow 3,7587704831... = AC \\ \\ 3,8 \approx AC[/tex]
Information on trigonometric ratios
[tex]\displaystyle \frac{OPPOCITE}{HYPOTENUSE} = sin\:θ \\ \frac{ADJACENT}{HYPOTENUSE} = cos\:θ \\ \frac{OPPOCITE}{ADJACENT} = tan\:θ \\ \frac{HYPOTENUSE}{ADJACENT} = sec\:θ \\ \frac{HYPOTENUSE}{OPPOCITE} = csc\:θ \\ \frac{ADJACENT}{OPPOCITE} = cot\:θ[/tex]
I am joyous to assist you at any time.