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### NOTA RINGKAS

1. CHAPTER 1 : LINES AND ANGLES II
2. CHAPTER 2 : POLYGONS II

Names of Polygons
 Name Sides Interior Angle Exterior Angle Triangle (or Trigon) 3 60° 120° Quadrilateral (or Tetragon) 4 90° 90° Pentagon 5 108° 72° Hexagon 6 120° 60° Heptagon (or Septagon) 7 128.571° 51.429° Octagon 8 135° 45° Nonagon (or Enneagon) 9 140° 30° Decagon 10 144° 36°

3. CHAPTER 3 : CIRCLES II

Definitions related to circles:
Arc:  A continuous piece of a circle is called an arc. In other words, any portion of the circumference of a circle is called an arc.
Chord: A straight line joining any two points on the circumference of a circle is called a chord.
Circumference: The perimeter of a circle is called its circumference
Diameter:  Any straight line drawn through the centre and terminating at both ways by the circumference is called a diameter.
Origin:  Origin refers to the center of a circle
Pi (  ):  An approximate value of  is 22/7 which is correct to two decimal places. A more accurate value of  is 3.14159 which is correct to five decimal places.
Radius: The constant distance of every point on the circle from its centre is called the radius of the circle. It is half of the diameter.
Sector:  A sector is that part of a circle, which lies between an arc and two radii joining the extremities of the centre. The most important sector is a quadrant, which is one-fourth of the circle.
Tangent of a circle:  It is a line perpendicular to the radius that touches only one point on the circle.
Circumference of a circle: = 2 r where  is 22/7 or 3.14159