Introduction Topic 4 sided Figures 1 Parallelogram 2

Introduction Topic : 4 -sided Figures. 1. Parallelogram 2. Rhombus 3. Trapezium

Parallelogram Properties 1. A parallelogram is a 4 -sided figure with 2 pairs of parallel sides. a c d b 2. The opposite angles are equal. Angle a = b c = d 3. Each pair of angles between 2 parallel sides add up to 180 deg. Angle a + c = 180 deg. b + d = 180 deg.

Practice 1 y 140 Angle y = 140 deg. Y=? Z=? z (Opp. Angles are equal) Angle Z = 180 deg. - 140 deg. = 40 deg. 140 deg + z = 180 deg.

Rhombus 1. A rhombus is a parallelogram with four equal sides. Line A Line B Line D Line B Line C Line D Line C 2. It has all the properties of a parallelogram.

Trapezium a b c d 1. A Trapezium has only 1 pair of parallel lines. 2. Each pair of angles between 2 parallel sides add up to 180 degrees. Angle a + b = 180 deg. Angle c + d = 180 deg. However, angle a + c does not equal 180 deg. The same goes to angle b + d.

Practice 2 B A 125 c C Angle c = ? 180 deg. - 110 deg. 180 deg. - 125 deg. 70 110 D ? x ? 55 deg.

Conclusion What have we learnt today? 1. We learn about 4 -sided figures which include Parallelogram, Rhombus and Trapezium. 2. We also learn about their properties. 3. Finally, we learn how to solve problems and find out the unknown angles after knowing their properties.

Hope you have enjoyed the lesson!!!