Respuesta :

goyangi
DC = 16

Explanation:

ABD is a right triangle (Angle ADB is a right angle)

Using the Pythagoras Theorem,
AB^2 = AD^2 + BD^2
AB^2 = 9^2 + 12^2
AB^2 = 81 + 144
AB^2 = 225
AB = 15

In triangle ABD,
sin(Angle A) = BD/AB
sin(Angle A) = 12/15
Angle A = sin^(-1)[12/15]
Angle A ≈ 53.13 degrees

In triangle ABC,
cos(Angle A) = AB/AC
cos(53.13) = 15/AC
AC = 15/cos(53.13)
AC ≈ 25

DC = AC - AD = 25 - 9 = 16

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