MATHEMATICS (POLYGONS)

• The word “polygon” comes from the Greek words “poly”, which means “many,” and “gon,” which means “angles.”
• A polygon is a union of non-collinear segments, the sides, on a plane that meet at their endpoints, the vertices, so that each endpoint (vertex) is contained by exactly two segments (sides).
• Regular polygon - a polygon with congruent sides and congruent angles.
• Convex polygons - A convex polygon is defined as a polygon with all its interior angles less than 180°. This means that all the vertices of the polygon will point outwards, away from the interior of the shape.
• Interior Angle - an angle formed inside the polygon by two adjacent sides.
• Exterior Angle -an angle that is both supplement and adjacent to one of its interior angles.
• The sum of an exterior angle and its adjacent interior angle is 180 degrees. The two angles also form a linear pair.
• The sum (S) of the measures of the angles of a covex polygon with 𝑛 sides is (𝒏 − 𝟐)𝟏𝟖𝟎.
• Triangle - A polygon with three sides and three angles.
• equilateral triangle -has three equal sides
• Isosceles Triangle -has two equal sides
• Scalene Triangle -has no equal sides
• Acute Triangle -has 3 angles < 90 degrees
• Right Triangle -has one angle = 90 degrees
• Obtuse Triangle has one angle > 90 degrees
• Quadrilateral - A four-sided polygon.
• Circle - set of all points that are the same distance from a fixed point.
• This fixed point is called the center of the circle.
• radius – a segment joining the center of the circle and any point on the circle.
• chord - a segment that connects any two points of a circle
• diameter - a chord that passes through the center of a circle
• central angle - an angle whose vertex is on the circle’s center, and whose sides intersect the circle at two points.
• Inscribed angle - angle formed in the interior of a circle when two chords intersect on the circle.
• arc - a portion of a circle determined by a central angle.