Question

Right angled triangle calculation.  the opposite is 150mm  and the only known angle is the right angle how can i calculate the other two sides and angle??

Answer 1

You can't.  One side and one angle is never enough to define a unique triangle.

If the side opposite the right angle is 150mm, the other 2 sides could be . . .

-- 75 and 129.9
-- 100 and 111.8
-- 110 and 101.98
-- 120 and 90
-- 130 and 74.83
-- both 106.07

or any one of an infinite number of other possibilities.

You need to know one more side, or one more angle.