# Math Help - Sin

1. ## Sin

Find sinB given that 0<B<(pie/2) and cosB=(1/5)

2. In a right-angled triangle sin = opposite/hypotenuse, cos = adjacent/hypotenuse. So if cos = 1/5, then consider a triangle with hypotenuse 5 and a side of 1. The other = ... by Pythagoras and so sin = ... / ???