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Angle one is top left, angle 2 is bottom left, angle 3 is bottom right, and the top right has no angle.

2006-11-27 13:00:10 · 4 answers · asked by Anonymous in Science & Mathematics Mathematics

definition of a parallelgram is opposing sides are parallel.

2006-11-27 13:06:57 · update #1

4 answers

Given the parallelogram ABCD with angle A supplementary to angle B, and angle C supplementary to angle B.

Since angle A supp to angle B, then AD parallel to BC because the interior angles on the same side of the transversal are supplementary.

Similarly, since angle C supp to angle B, then AB parallel to DC because the interior angles on the same side of the transversal are supplementary.

Therefore ABCD is a parallelogram by definition.

Q.E.D.

2006-11-27 13:19:00 · answer #1 · answered by ironduke8159 7 · 0 0

assume it is a parallelogram. since it is a parallelogram the angles opposite to each other are the same. and it you ald all the angles together you should get 360. the angles one and three are the same and angles two and four are the same. making it a parallelogram. okay now the side of a parallelogram are parallel lines so the angle formed by angle one and two are 180. and since three is the same as one it is also supplementary. two angles that add up to 180 are supplementary.

2006-11-27 13:08:27 · answer #2 · answered by bagi2009 2 · 0 0

If angle 1&3 are sup to the same angle then angle 1= angle 3 the unnamed angle must be equal to angle 2 because it must be suplemental to angle 3

with me so far

since opposing angles are suplemental it must be a parrallelagram(if direct angles are like you have a trapezoid)

if you are still confused draw a picture

2006-11-27 13:09:31 · answer #3 · answered by TJ C 1 · 0 0

if angles 1 and 3 are equal and if angles 2and 3 or 1and 2 add up to be 180.

2006-11-27 13:04:38 · answer #4 · answered by gamerx66x 2 · 0 0

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