Respuesta :

For this case what you should do is use the following trigonometric relationship:
 sine (60) = (z) / (a + b)
 Clearing z we have:
 z = (a + b) * sine (60)
 Substituting:
 z = (15) * sine (60)
 z = 15 * (root (3) / (2))
 Answer:
 z = 15 * (root (3) / (2))