Answer:
B: 17.8°
Step-by-step explanation:
Actually, you want the measure of Angle A, not m. "m" stands for "measure of" in this setting.
Use the Law of Sines to find Angle A.
a c
--------- = --------
sin A sin C
In this case we have:
11 18
--------- = ------------
sin A sin 30°
Since sin 30° = 1/2, we have:
11 18
--------- = ------------
sin A 1/2
Cross-multiplying produces: (1/2)(11) = 18(sin A), and:
11/2
sin A = -------------------- = 11/36 = 0.30556
18
We must now use the inverse sine function to determine A from sin A = 0.30556:
arcsin 0.30556 = 0.3105 radians
Converting 0.3105 rad to degrees, we get A = 17.79°.
This agrees with answer B: 17.8°
