I am solving a triangle using the law of sines:
a = 75 b = 100 c = ?
Angle A = 30° Angle B = ? Angle C = ?
I did
sinB / 100 = sin30 / 75
SinB = (100sin(30°))/75
SinB = .6667
Sin^-1 (.6667) = Angle B = 41.8°
However in the online calculator I used it Picture of the online calculators work is saying that using those same numbers Angle B is = to 71.2°
$\endgroup$ 71 Answer
$\begingroup$The online calculator is incorrect - be wary of many online sites, they may be using a formula of some other kind.
Your working is correct and the answer was confirmed to be 41.81 degrees using the law of sines.
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