In triangle ABC, angle C = 90 BC = 10 BH = 6 CH- height. Find sin A

The height drawn from the top of the right angle divides the triangle into two similar to each other and similar to the original one. We have similar tracks: CAB, US and NSV. From the similarity we have the ratio: AB / SV = SV / NV, whence AB = 50/3.
SinA is the ratio of the opposite leg to the hypotenuse, i.e. CB / AB = 0.6
SinA = 0.6.
open: 0.6