Question

solve triangle ABC which have angleA=250:251;angleB=600:511anda=3:82:Findc:

Answer 1

Answer on Question #51008-Math-Trigonometry

Solve triangle ABC which have angle $A = 25{}^\circ$; angle $B = 60{}^\circ$ and $a = 3$. Find c:

Solution

The angle C is

$$C = 180{}^\circ - (A + B) = 180{}^\circ - (25{}^\circ + 60{}^\circ) = 95{}^\circ.$$

According to the Sine Rule:

$$\frac{a}{\sin A} = \frac{c}{\sin C}.$$

Thus,

$$c = a \frac{\sin C}{\sin A} = 3 \frac{\sin 95{}^\circ}{\sin 25{}^\circ} = 7.1.$$

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