The cosine of an angle is equal to the sine of its complement. In a right triangle, angle A is the complement of angle B. So, ...
cos(A) = sin(B)
cos(A) = 7/25
Answer from: Quest
start with a line segment pq that we will copy. mark a point r that will be one endpoint of the new line segment. set the compasses' point on the point p of the line segment to be copied. adjust the compasses' width to the point q. the compasses' width is now equal to the length of the line segment pq.