The term quadrilateral refers to a figure enclosed by the four sides that are not equal. And the sum of all angles of a quadrilateral is always equal to 360 degrees.
Types of a Quadrilateral
1. Parallelogram
It is an enclosed figure with four sides.
The parallelogram is a figure whose opposite sides are equal.
2. Rectangle
It is an enclosed figure with four sides.
The rectangle is a figure whose opposite sides are equal.
Every angle of the rectangle is always equal to 90 degrees.
3. Square
The square is an enclosed figure with four equal sides.
Every angle of the rectangle is always equal to 90 degrees.
4. Rhombus
The rhombus is a parallelogram whose all sides are equal.
5. Kite
It is a figure whose adjacent angles are equal.
Problem
If ABFE is a trapezium, then prove that C is the midpoint of BF and AB is parallel to EF, whereas D is the midpoint of AE. And EF is parallel to DC.
Solution:
BE cut DC at a point, i.e., G.
Now in
With the help of the midpoint theorem, G is known as the midpoint of EB.
In the ∆, G is the midpoint of BE and GC is parallel to EF.
With the midpoint theorem, C becomes the midpoint of BF.
It is proved that c is the midpoint of the side BF.
Learning Videos for 9th Grade Math - Quadrilaterals