A rhombus is a quadrilateral that has 4 congruent sides and 4 right angles. According to Theorem 6.15 states, ” If a parallelogram is a rhombus, then its diagonals are perpendicular.” Theorem 6.16 also states that ” If a parallelogram is a rhombus, then each diagonal bisects a pair of opposite angles.” Every square is a rhombus, and every rhombus can be a square, if all its angles are 90 degrees. A rhombus can also be a rectangle if the sides of the rectangle are all equal length.
A trapezoid is is a quadrilateral with only one pair of parallel sides. The properties of trapezoids are following: the lower and upper base angles are congruent, the diagonals are congruent, and the legs are congruent by definition. Theorems 6.21, 6.22, and 6.23 discuss if a trapezoid was an isosceles trapezoid, and what the model would look like. There’s also a theorem called Theorem 6.24, or the Trapezoid Mid-segment Theorem. This theorem states that “the mid segment of a trapezoid is parallel to each base and its measure is one half the sum of the lengths of the bases.”
Jillian Pou Geometry Blog 