Respuesta :

Answer:

60 degrees.

Step-by-step explanation:

sin(theta/3+10)=costheta

Since sin theta = cos (90 - thets):

theta / 3 + 10 = 90 - theta

theta/3 + theta = 90 - 10

4/3 theta = 80

theta =  80 * 3/4 = 60 degrees.