A right-angled triangle is a triangle that has a right angle. The angles inside a shape ... To prove \(a + b + c = 180^\circ\), firstly draw a line parallel to one side of the triangle.

any angle that is bigger than a right angle but less than a straight, flat line (91-179 degrees – remember them as obese or fat angles). Now, think back to our pizza; if we slice a pizza into ...