LINES AND ANGLES
• LINES - a straight one- dimensional figure that has no thickness and extends endlessly in both directions. • ANGLES - An angle is a combination of two rays (half-lines) with a common endpoint. The later is known as the vertex of the angle and the rays as the sides, sometimes as the legs and sometimes the arms of the angle. • ACUTE ANGLE - Acute angles measure less than 90 degrees • RIGHT ANGLE - a right angle is an angle of exactly 90 degrees • OBTUSE ANGLE - an angle between 90° and 180° • REFLEX ANGLE- any angle that is more than 180 degrees (half circle) and less than 360 degrees • STRAIGHT ANGLE - a straight angle is an angle equal to 180 degrees • ...