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Not all things with four sides have to be squares or rectangles! We will now broaden our understanding of quadrilaterals.
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