Question 47184
  
  Sum of the angles in a triangle = 180 degrees.
 
  angle B + angle C = 90 degrees.             (given)
 
  So angle A  =  180-90 = 90 degrees.
 
  But angle A is thrice the angle B.
 
  So  angle B = 1/3 of angle A
  
              = 1/3 * 90 = 30 degrees.
 
  So angle C = 90-30 = 60 degrees. Because angle B + angle C = 90 degrees (given)
  
angle A = 90 degrees; angle B = 30 degrees; angle C = 60 degrees.  Answer.