If A is the right angle of the triangle, B and C would be the two acute angles of the triangles.
Let B angle is 4 times the C angle. We will have B = 4C (1) since A is the right agle the two other angles
of the triangle will have the sum of 90 degrees. That is B + C = 90 (2). Solving the system of equations (1) and (2) we have the solution. the (2) becomes 4C + C = 90 or 5C = 90 or C=90/5 = 18
from (2) we have B = 90 - C. Then B = 90-18 =72 degrees.
72 = 4*18