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Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals.
"Quad" means "four" and "lateral" means "line." A quadrilateral is literally a shape with four sides (lines) and four angles. Let's learn the difference between concave and convex quadrilaterals as well as trapezoids, parallelograms, and ...
How about this: we are given a 4-sided shape and asked to determine whether its properties qualify it to be called a quadrilateral (or category of quadrilaterals). Check it out.
Is a kite a quadrilateral? Is it a rhombus? A parallelogram? Let's find out.
Take a look at the given data and determine what type of quadrilateral we have.
Identify quadrilaterals based on pictures or attributes. Quadrilaterals included are parallelograms, rhombuses, rectangles, and squares.
Sal proves that a figure is a parallelogram if and only if opposite sides are congruent.
Sal proves that a quadrilateral is a parallelogram if and only if its diagonals bisect each other.
Sal proves that opposite angles of a parallelogram are congruent.
Sal proves that the diagonals of a rhombus are perpendicular, and that they intersect at the midpoints of both.
Sal proves that we can find the area of a rhombus by taking half the product of the lengths of the diagonals.
Guess what's interesting about the opposite sides of a parallelogram? That's right....they are parallel! Let's find the area--base times height
Proving whether a special quadrilateral can exist
Proof that the diagonals of a rhombus are perpendicular bisectors of each other