1. Given that the side length of a diamond is 5cm and the diagonal length is 5cm, the maximum internal angle of a diamond is _ _ _ _ _.

Answer 120

2. The distance between the two right-angle vertices of the right-angle trapezoid and the midpoint of the opposite waist ()

A. unequal

C. it may or may not be equal. This is impossible to compare.

Answer a

3. Among the following propositions, the correct one is ()

Two quadrilaterals with equal diagonals are parallelograms.

Two quadrangles with equal diagonal lines and perpendicular to each other are rectangles.

A quadrilateral with two diagonal lines bisecting each other vertically is a diamond.

A quadrilateral with two diagonal lines bisecting each other and being equal is a square.

Answer c

4. If the diagonal length of a square is 2 cm, then the area of this square is ().

A.4 B.2 C. D

Answer b