TRAPEZOID AND ISOSCELES TRAPEZOID

TRAPEZOID

• The bases are parallel by definition.
• Each lower base angle is supplementary to the upper base angle on the same side.
• the perimeter of trapezoid = a+b+c+d (*the sum of all side lengths)
• The area of trapezoid = (a+b/2) × h (*average of the two base lengths times the altitude)

ISOSCELES TRAPEZOID

• The diagonals have the same length.
• The base angles have the same measure.
• An isosceles triangle is formed by the base and the extensions of the legs. 
• The segment that joins the midpoints of the parallel sides is perpendicular to them.
• Opposite angles are supplementary

Bibliography : 

• Web Page of BBC
• Web Side of Mathsisfun