The shape you're describing is a kite. A kite has two pairs of adjacent sides that are equal in length, and its diagonals intersect at right angles (90 degrees). However, the lengths of the diagonals are not equal, which distinguishes it from a rhombus.
None but the diagonals intersect at 90 degrees
A rectangle would fit the given description
A Quadrilateral Kite!
Because it has 4 sides of equal lengths and its diagonals cross at 90 degrees. It looks like a tilted square with opposite parallel sides
A rhombus.
A kite
The sides are equal The angle between adjacent sides is 90 degrees There are two diagonals The diagonals are equal in length The diagonals make 90 degrees with each other The diagonals make 45 degrees with the sides
A parallelogram
rhombus
A rhombus has unequal diagonals which intersect at right-angles.
Square (also rhombus)
The shape you are describing is a rhombus. A rhombus has two pairs of parallel sides, with opposite sides being equal in length. The diagonals of a rhombus are also equal in length, but they do not intersect at 90 degrees; instead, they intersect at a 90-degree angle.
No but its diagonals bisect each other at 90 degrees
None but the diagonals intersect at 90 degrees
A rectangle would fit the given description
A parallelogram (or rectangle) which is not a rhombus (or square).
prove any two adjacent triangles as congruent