Instruction
1
From the name of a right triangle it is clear that one of its angles is a direct. Regardless of whether it is an isosceles right triangle or not, it always has one angle equal to 90 degrees. If given a right triangle that is both isosceles and then, based on the fact that the figure is a straight angle, find two angles at its base. These angles are equal, so each of them has a value equal to:

α=180°- 90°/2=45°
2
In addition to the above, it is also possible the other case, when the triangle is rectangular, but is not isosceles. In many problems the angle of the triangle is 30° and the other 60°, because the sum of all angles in a triangle must equal 180°. If given the hypotenuse of a right triangle and side angle can be found from matching the two sides:

sin α=a/c where a is the side opposite to the hypotenuse of a triangle, with the hypotenuse of the triangle

Accordingly, α=arcsin(a/c)

Also the angle you can find the formula for cosine:

cos α=b/c where b is the adjacent side to the hypotenuse of the triangle
3
If you know only two sides, the angle α can be found according to the formula of the tangent. The tangent of this angle is equal to the ratio of opposite over adjacent:

tg α=a/b

From this it follows that α=arctg(a/b)

When the straight angle and one of the corners found by the above method, the second is as follows:

ß=180°-(90°+α)