Study Online and Download Notes of Mathematics 9th Unit 11: Parallelograms and Triangles. Before proceeding to prove the theorems in this unit the students are advised to recall definitions of polygons like parallelogram, rectangle, square, rhombus, trapezium etc. and in particular triangles and their congruency.
Study Online and Download Notes of Mathematics 9th Unit 11: Parallelograms and Triangles. Before proceeding to prove the theorems in this unit the students are advised to recall definitions of polygons like parallelogram, rectangle, square, rhombus, trapezium etc. and in particular triangles and their congruency.
After studying this unit, the students will be able to:
- prove that in a parallelogram the opposite sides are congruent, the opposite angles are congruent, the diagonals bisect each other.
- prove that if two opposite sides of a quadrilateral are congruent and parallel, it is a parallelogram.
- prove that the line segment, joining the midpoints of two sides of a triangle, is parallel to the third side and is equal to one half of its length.
- prove that the medians of a triangle are concurrent and their point of concurrency is the point of trisection of each median.
- prove that if three or more parallel lines make congruent segments on a transversal, they also intercept congruent segments on any other line that cuts them.
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