Square: the surface of the indoor switch, the surface of the square table, the surface of the clock (square), the surface of the square stool, the side of the computer host, etc.

Rectangle: notebook, cabinet, table, mirror, box, computer, drawer, floor tile, paper bag, book, frame, CD box, watch, shoe box, medicine box, biscuit box, box, building block . ?

Triangles: umbrellas, hats, colorful flags, lampshades, sails, small pavilions, snowy mountains, roofs, watermelons cut into triangles, torch ice cream, edges of tropical fish, butterfly wings, rockets, bamboo shoots, pagodas , pyramids, briefs, triangles used on machines, certain road signs, the Yangtze River Delta, cable-stayed bridges, etc.

Rhombus: paper towel, diamond table, diamond stool, diamond box, crystal, diamond window.

Trapezoid: a standard block of gold, with a trapezoidal side, glass on the car door, a trolley pulling cement at the construction site, a tripod, and some flower pots. ?

Extended information:

Square judgment:

1: A rhombus with equal diagonals is a square.

2: A rhombus with one right angle is a square.

3: A rectangle with perpendicular diagonals is a square.

4: A set of rectangles with equal adjacent sides is a square.

5: A set of parallelograms with equal adjacent sides and one right angle is a square.

6: A parallelogram whose diagonals are perpendicular and equal to each other is a square.

7: A quadrilateral whose diagonals are equal and bisect each other perpendicularly is a square.

8: A quadrilateral with equal adjacent sides and three right angles is a square.

9: A quadrilateral that is both a rhombus and a rectangle is a square

Common ways to determine a rectangle:

1. A parallelogram with one right angle is a rectangle .

2. A parallelogram with equal diagonals is a rectangle.

3. A parallelogram with adjacent sides perpendicular to each other is a rectangle.

4. A quadrilateral with three right angles is a rectangle.

5. A quadrilateral whose diagonals are equal and bisect each other is a rectangle.

6. (Through parallelograms)

In parallelogram ABCD: ∠BAD=90° or BD=AC? ∴Parallelogram ABCD is a rectangle.

7. (Through the quadrilateral)

In the quadrilateral ABCD: ∠ABC=∠BCD=∠CDA=90°, ∴The quadrilateral ABCD is a rectangle.

Trapezoid judgment:

1. A quadrilateral in which one set of opposite sides is parallel and the other set of opposite sides is not parallel is a trapezoid.

2. A set of parallel and unequal quadrilaterals is a trapezoid