Respuesta :

Answer:

[tex] s = 14.1 [/tex]

Step-by-step explanation:

Find s using the Law of Cosines:

m < S = 31°

SR = q = 21

SQ = r = 9

QR = s = ?

Thus,

[tex] s^2 = r^2 + q^2 - 2(r)(q)*cos(S) [/tex]

[tex] s^2 = 9^2 + 21^2 - 2(9)(21)cos(31) [/tex]

[tex] s^2 = 81 + 441 - 378*0.8572 [/tex]

[tex] s^2 = 522 - 324.0216 [/tex]

[tex] s^2 = 197.9784 [/tex]

[tex] s = \sqrt{197.9784} [/tex]

[tex] s = 14.07 [/tex]

[tex] s = 14.1 [/tex] (to the nearest tenth)