All triangles have three angles that always add up to 180?: A + B + C = 180?. A right angled triangle is a triangle that has a right angle (90?) in it. Read on about this from www.mathsisfun.com/right_angle_triangle.html.
How can you not know how many degrees are in a right triangle!!! I knew that when I was 6, literally! It's 90 degrees, you can figure it out by knowing how many degrees are in a circle(360) half a circle(180) and half of 180 is (90) if you add 90+90 it =180 add 180+180 that = 360 That's simple math my friend.