Question 413660
Not all quadrilaterals with congruent diagonals are rectangles. Draw an isosceles trapezoid, and you'll see.


{{{drawing(200, 200, 0, 10, 0, 10,


line(1, 2, 9, 2),
line(9, 2, 7, 9),
line(7, 9, 3, 9),
line(3, 9, 1, 2),
line(3, 9, 9, 2),
line(1, 2, 7, 9)

)
}}}