Answer:
[tex] r = 17.5 [/tex]
Step-by-step explanation:
Given ∆TRS,
Where,
m < R = 105°
TR = s = 15
RS = t = 6
ST = r = ?
Find r using the Law of Cosines.
[tex] r^2 = s^2 + t^2 - 2*s*t*cos(R) [/tex]
Plug in the values stated above into the formula
[tex] r^2 = 15^2 + 6^2 - 2*15*6*cos(105) [/tex]
[tex] r^2 = 225 + 36 - 180*(-0.2588)[/tex]
[tex] r^2 = 261 + 46.584 [/tex]
[tex] r^2 = 307.584 [/tex]
[tex] r = \sqrt{307.584} [/tex]
[tex] r = 17.5 [/tex] (to the nearest tenth)
