Yes.
Although the definition of a parallelogram is "a quadrilateral with both pairs of opposite sides parallel", the only way for a quadrilateral to include opposite sides of equal length is if the included angles are the same, and hence the sides are parallel.
(Hint : draw a diagonal to a parallelogram. You can show that one of the two triangles formed is the mirror image of the other, which immmediately proves that each pair of opposite sides is equal.)
I can't offer a full proof, but I can suggest some possibilities that will lead you to your proof. In a parallelogram, you can easily demonstrate that the angles formed by a cord extending between parallel lines and the parallel lines themselves, and that are formed on opposite sides of the cord, are equal. This will work for both pairs of triangles in the parallelogram, and can be applied to all of the angles at the corners of the parallelogram. This will lead you to demonstrating that the pairs of triangles "pointing" to each other (not adjacent pairs) are similar, and in fact congruent. From there it is not difficult to establish that the connected sections of the two interior cords are equal.
A rectangle is a parallelogram. However, parallelograms only need two sets of parallel lines, not necessarily with all right angles as in the rectangle : they can also be rhomboids and rhombi. The shared features are - parallel opposite sides - equal opposite angles - supplementary adjacent angles
A trapezoid has one pair of parallel sides. A parallelogram has two pairs of parallel sides.
Yes, those words are antonyms. However, the antonym pairs are usually - little, opposite of big - small, opposite of large
The numbers below are the factor pairs of 44. Multiplied together they equal 44: (1, 44) (2, 22) (4, 11)
False. If both pairs of opposite angles of a quadrilateral are congruent then the quadrilateral is a parallelogram.
true
A parallelogram.
true
Yes, because a square is a parallelogram
A parallelogram is a geometric quadrilateral with two pairs of parallel sides. The opposite sides and opposite angles are equal in length.
Yes. A parallelogram is a quadrilateral in which both pairs of opposite sides are parallel.
Diagonally opposite pairs of angles will always be equal, but the only time all angles in a quadrilateral parallelogram are equal is when that shape is a rectangle.
If a quadrilateral has two pairs of opposite congruent sides, then the quadrilateral is a parallelogram.
A parallelogram is such a shape.
A quadrilateral is a parallelogram if it has two pairs of (opposite) sides that are parallel.
A quadrilateral with both pairs of opposite sides congruent is a parallelogram.