Use the Law of Sines. Find the indicated measure to the nearest tenth. In Triangle RST, m∠R = 78, m∠T = 39, and TS with line on top = 19 in. Find RS. a. 12.2 in c. 15.8 in b. 10.7 in d. 20.7 in

RS = 12.2 in ⇒ answer (a)

Step-by-step explanation:

∵ m∠R = 78°, m∠T = 39°, TS = 19

∵ By using sin Rule:

∵ ST/sin∠R = RS/sin∠T

∴ 19/sin78 = RS/sin39

∴ RS = (19 * sin39) : sin 78 = 12.2 in ⇒ answer (a)