In triangle ABC, the angle is 90 degrees cosA is 0.31, find sin B.

Given:
right-angled triangle ABC,
angle С = 90 degrees,
cos A = 0.31.
Find sin B -?
Decision:
1) Consider a right-angled triangle ABC. Since the sum of the degree measures of the angles of any triangle is 180 degrees, and the angle C = 90 degrees, then the angle A = 90 is the angle B.
2) According to the reduction formula:
cos A = cos (90 – B) = sinB.
Therefore (since cos A = 0.31 according to the problem statement):
sin B = 0.31.
Answer: 0.31.