"Given quadrilateral ABCD with A(0,0) B(4,2) C(3,3) and D(1,2), prove that ABCD is a non-isosceles trapezoid"

I don't understand how to put this as a proof, since I have to include formulas and reasons. Wouldn't a non-isosceles trapezoid be a normal trapezoid? Really lost..

2 answers

yes, it is a "normal" trapezoid; it just means that its two non-parallel sides are not the same length. So, all you have to do is show that two of the sides of ABCD are parallel, and the others, not.

Clearly, AB and CD are parallel, since they have the same slope.

So, now you just have to show that AD≠BC
What you want to do is find the slope of all 4 sides and you should get to slopes the same...and follow a regular proof till you say its a trap.then to prove its not isosceles you use the for sides again but this time with the distance formula...and then you go along answering the proof