Angle in a semi-circle is a right angle
- Yoong Kheong
Blue pt for : 1. Moving the point respective pt A and C along the circumference. Red pt for: 1. Moving the centre, 0. Black pt F for: 1. Moving the point F hence rotating the dotted straight line through B and O. Slide for: Changing the radius of the circle. Exploration: Check the angle in the semi-circle. Use the radius and move the centre to show the angle property of circle - Angle in a semi-circle is a right angle.