Respuesta :

Answer:

Step-by-step explanation:

You need the Law of Cosines for this, namely:

[tex]x^2=21^2+14^2-2(21)(14)cos58[/tex] where x is the missing side.

[tex]x^2=441+196-311.5925[/tex] and

[tex]x^2=325.4075[/tex] so

x = 18.0 or just 18