Can someone please help solve this question (with a diagram)?

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1 Answer

Law of sines

Law of cossines

Explanation:

|AB| = x, |AD| = y, angle DAC = alpha

angle BAC = 180 - 43 - 72 = 65^0

angle BAD = 65^0 - alpha

|BD| = |DC| = 4

frac{x}{sin 72^0} = 8 / sin 65^0

x = 8,395 cm

y^2 = x^2 + 4^2 - 2 * x * 4 * cos 43^0

y = 6,112 cm

frac{4}{sin (65^0 - alpha)} = y/sin 43^0

sin (65^0 - alpha) = (4 * sin 43^0) / y = 0,44632

65^0 - alpha = 26,508

alpha = 38,4919 = 38^0 29.5 min