Conversation so far:
which type of triangle must have perpendicular lines
In a right triangle, two sides are always perpendicular. The measurements of these sides are used to calculate the area of a right triangle.
which type of triangle has obtuse sides
In an obtuse triangle, one angle is greater than a right angle—it is more than 90 degrees. An obtuse triangle may be isosceles or scalene.
what is the difference between an isosceles and a scalene triangle
In an isosceles triangle, two sides are the same length. In a scalene triangle, none of the sides are the same length.

Question: what is the formula
Self-contained rewrite: what is the formula for the degrees of an angle of a right triangle