Determine if the quadrilateral is an isosceles trapezoid

Question

The coordinates of the vertices of quadrilateral ABCD are A (0,0), B(a,b), C (c,b) and D (a+c,0). Using the coordinates, determine if quadrilateral ABCD is an isosceles trapezoid.

Answer 1

Determine slopes of BC and AD. If slopes are the same, the two bases are parallel.

Determine length so of AB and CD. If lengths are the side, the two sides are equal.

If both of the above conditions are true, then ABCD is an isosceles trapezoid.