proof opposite angles of a parallelogram are congruent?
473334
THEOREM: If a quadrilateral has 2 sets of opposite angles congruent, then it is a parallelogram. ... THEOREM: If a quadrilateral has diagonals which bisect each other, then it is a parallelogram. * THEOREM: If a quadrilateral has one set of opposite sides which are both congruent and parallel, then it is a parallelogram.
438083
The opposite angles of a parallelogram are equal (and conversely: if the opposite angles of a quadrilateral are equal, it is a parallelogram). The diagonals of a parallelogram bisect each other (and conversely: if the diagonals of a quadrilateral bisect each other, it is a parallelogram).
45277
The first way to prove that the diagonals of a rectangle are congruent is to show that triangle ABC is congruent to triangle DCB. Since ABCD is a rectangle, it is also a parallelogram. Since ABCD is a parallelogram, segment AB ≅ segment DC because opposite sides of a parallelogram are congruent.
92358
['Opposite sides are congruent (AB = DC).', 'Opposite angels are congruent (D = B).', 'Consecutive angles are supplementary (A + D = 180°).', 'If one angle is right, then all angles are right.', 'The diagonals of a parallelogram bisect each other.']
624125
DEFINITION: A parallelogram is a quadrilateral with both pairs of opposite sides parallel. ... THEOREM: If a quadrilateral has 2 sets of opposite angles congruent, then it is a parallelogram. * THEOREM: If a quadrilateral has consecutive angles which are supplementary, then it is a parallelogram.
273100
The opposite angles of a parallelogram are always the same.
1331524
If both pairs of opposite sides of a quadrilateral are congruent, then the quadrilateral is a parallelogram. If one pair of opposite sides of a quadrilateral are parallel and congruent, then the quadrilateral is a parallelogram.
367029
When a parallelogram is divided into two triangles we get to see that the angles across the common side( here the diagonal) are equal. This proves that the opposite angles in a parallelogram are also equal. ... The diagonals of a parallelogram are not of equal length.
161091
A parallelogram is a quadrilateral whose opposite sides are parallel. The opposite angles of a parallelogram are equal. The opposite sides of a parallelogram are equal. The diagonals of a parallelogram bisect each other.
1462697
DEFINITION: A parallelogram is a quadrilateral with both pairs of opposite sides parallel. THEOREM: If a quadrilateral is a parallelogram, it has 2 sets of opposite sides congruent. THEOREM: If a quadrilateral is a parallelogram, it has 2 sets of opposite angles congruent.
804494
THEOREM: If a quadrilateral has diagonals which bisect each other, then it is a parallelogram. THEOREM: If a quadrilateral has one set of opposite sides which are both congruent and parallel, then it is a parallelogram. This last method can save time and energy when working a proof!
506871
A parallelogram must be a rhombus when its 1) Opposite sides are congruent. 2) Opposite sides are parallel.
952519
If a quadrilateral is a parallelogram, then its opposite sides are congruent. If a quadrilateral is a parallelogram, then its opposite angles are congruent. If a quadrilateral is a parallelogram, then its diagonals bisect each other.
730621
Angles ABC and CDA are congruent according to a property of parallelograms (opposite angles congruent). Angles BAC and DCA are congruent by the Same-Side Interior Angles Theorem. Angles BAC and DCA are congruent by the Alternate Interior Angles Theorem.
1439142
DEFINITION: A parallelogram is a quadrilateral with both pairs of opposite sides parallel. THEOREM: If a quadrilateral is a parallelogram, it has 2 sets of opposite sides congruent. ... THEOREM: If a quadrilateral has 2 sets of opposite angles congruent, then it is a parallelogram.
1428910
The opposite sides of a parallelogram are equal. ABCD is a parallelogram. To prove that AB = CD and AD = BC.
913066
Consecutive angles of a parallelogram are congruent. Diagonals of a parallelogram bisect each other. The four angles of a rhombus are right angles.