A trapezoid whose waist is perpendicular to the bottom is called a right-angled trapezoid.

Nature:

A right-angled trapezoid has two angles that are right angles.

Judge:

A trapezoid with a right angle inside is a right-angled trapezoid.

The basic definition of right-angle trapezoid knowledge point 2 in junior two mathematics;

A trapezoid with right angles is called a right trapezoid.

Area formula:

S= (upper bottom+lower bottom) × height ÷2

A trapezoid is a quadrilateral with parallel upper and lower sides. You can divide it into two triangles with the same height according to a diagonal line. The triangle area formula is "base times height divided by 2", so the trapezoid is: "upper base times height divided by 2"+"lower base times height divided by 2" = "upper base plus lower base times height divided by 2".

Another formula:

"centerline × height"

The basic property is that two bottoms are parallel and unequal, two waists are not parallel and unequal, and two corners on one waist are right angles.

It is characterized in that AD//BC, ∠ B = 90, then ∠ A = 90, ∠ C+∠ D = 180 in the right-angled trapezoidal ABCD.

Important nature:

The distance between the midpoint of the right-angled trapezoid inclined waist and the two endpoints of the right-angled waist is equal.

develop

isosceles trapezoid

definition

An isosceles trapezoid is called an isosceles trapezoid.

nature

1。 The two waists of an isosceles trapezoid are equal.

2。 Having an isosceles trapezoid on the same base. The two base angles are equal.

3。 The two diagonals of an isosceles trapezoid are equal.

4。 The isosceles trapezoid is an axisymmetric figure, and the symmetry axis is the line connecting the midpoints of the upper and lower bottom surfaces (the line passing through the midpoints of the two bottom surfaces).

decision

① isosceles trapezoid is isosceles trapezoid;

② Two trapezoid with equal angles on the same base are isosceles trapezoid;

③ A trapezoid with equal diagonal lines is an isosceles trapezoid;