Answer:
31.8°
Step-by-step explanation:
The mnemonic SOH CAH TOA reminds you of the relevant trig relation:
Sin = Opposite/Hypotenuse
Here, that means ...
sin(A) = BC/AC
sin(x°) = 39/74
The arcsine function is used to find the angle when its sine is known.
x° = arcsin(39/74) ≈ 31.8°
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Additional comment
You may be more familiar with the notation ...
[tex]x^\circ=\sin^{-1}{\left(\dfrac{39}{74}\right)}[/tex]
This is how the arcsin (inverse sine) function is identified on most calculators.
