## UNDERSTANDING QUADRILATERALS - ESSENTIAL POINTS

• Quadrilateral is a polygon having 4 sides.
• Parallelogram: A quadrilateral with pair of parallel opposite sides.
1. Opposite sides are equal.
2. Opposite angles are equal.
3. Diagonals bisect one another.
• Rhombus: A parallelogram with sides of equal length.
1. All the properties of a parallelogram.
2. Diagonals are perpendicular to each other.
• Rectangle: A parallelogram with a right angle.
1. All the properties of a parallelogram.
2. Each of the angles is a right angle.
3. Diagonals are equal.
• Square: A rectangle with sides of equal length.
1. All the properties of a parallelogram, rhombus and a rectangle.
• Kite: A quadrilateral with exactly two pairs of equal consecutive sides
1. The diagonals are perpendicular to one another.
2. One of the diagonals bisects the other.
3. One pair of opposite angles are equal.
• Trapezium: A quadrilateral having exactly one pair of parallel sides.
• Line segment connecting two non-consecutive vertices of a polygon is called diagonal.
• Convex: The measure of each angle is less than 180°.
• Concave: The measure of at least one angle is more than 180°.
1. Sides: Line segments joining the points.
2. Vertices: Point of intersection of two consecutive sides.
3. Opposite sides: Two sides of a quadrilateral having no common end point.
4. Opposite Angles: Two angles of a quadrilateral not having a common arm.
5. Diagonals: Line segment obtained by joining the opposite vertices.
6. Adjacent Angles: Two angles of a quadrilateral having a common arm.
7. Adjacent Sides: Two sides of a quadrilateral having a common end point
• Sum of external angles of a polygon is always 360°.