When a triangle is formed inside a semicircle, two lines from either side of the diameter meet at a point on the circumference at a right angle. The angle in a semicircle is a right angle of \(90 ...

The angle at the circumference in a semi-circle is 90°. Angle STU = 90° Angles in a triangle add up to 180°. The angle on a straight line is 180°. The angle VOY = 180°. The angle at the ...