How to prove that a quadrilateral is an isosceles trapezoid

Prove that the two sides that are not adjacent to each other are equal or have equal angles.

Shi Can": You are so coincidental.

1) The two waists are equal, and the two bottom angles are equal, which is an isosceles trapezoid.

b) The two waists are equal, the two diagonals are equal, and it is an isosceles trapezoid.

3) The two waists are equal, the diagonal complementarity is complementary, and it is a trapezoidal shape of the waist of equal filial piety.

iv) One group of opposite sides is parallel, and the other group of opposite sides are equal, which is isosceles trapezoidal.

There are also some that can be pushed down from the above.

Good luck and see you again in Lap Rock.

Mistake. Analysis:

Judging according to the meaning of the isosceles trapezoid, it will be clear that there is a group of opposites that are parallel, and a group of quadrilaterals that are not parallel to the sides of the return to the mausoleum and are equal in length are called isosceles trapezoids

Judging by the meaning of an isosceles trapezoid, an isosceles trapezoid is a quadrilateral shape with only one set of opposing sides parallel and another set of opposing sides that are not parallel and of equal length

Therefore, the statement of the stem is wrong

So the answer is:

Comments: This question examines the characteristics of trapezoids, as well as the definition of isosceles trapezoids and the classification of trapezoids

The isosceles trapezoidal proof method is as follows:

1. One group of opposites is parallel and the answers are not equal, and the other group of opposites is equal to the four-sided shape slippery is the isosceles ladder sail lifting wax shape;

2. A trapezoid with equal diagonals is an isosceles trapezoid;

3. A trapezoid with two equal waists is an isosceles trapezoid;

4. Two trapezoids with equal bottom angles are isosceles trapezoids.

Parallelogram: Two sets of opposite sides are parallel.

The two groups of opposite sides are equal.

A set of opposing sides is parallel and equal.

The diagonal lines are bisected with each other.

Trapezoid: A set of opposites parallel and one set of opposites that are not parallel to each otherIsosceles trapezoidal: One set of opposites parallel and one set of opposites not parallel, waist equal rectangle: Three angles equal to 90°

The diagonals are bisected and equal to each other.

There is a parallelogram with an angle equal to 90°.

A parallelogram with equal diagonals.

Rhombus: The four sides are equal.

A parallelogram with equal margins.

The diagonals are bisected perpendicular to each other.

Square: A rectangle with equal edges.

There is a diamond with an angle equal to 90 °.

Parallelogram: two sets of opposite sides are parallel or equal; A set of opposing sides is parallel and equal. The diagonal lines are bisected with each other. The two groups are diagonally equal, etc.

Trapezoid: Generally defined (a set of opposite sides that are parallel but not equal; One set of opposing edges is parallel, and the other set of opposing edges is not parallel).

Isosceles trapezoidal: the trapezoidal base plus the diagonal is equal in length; The opposite sides that are not parallel are equal in length.

Rhombus: quadrilaterals are equal on each side; The adjacent sides of the parallelogram are equal in length; The parallelogram is diagonally perpendicular; The parallelogram bisects the angle diagonally.

Rectangle: four right-angled quadrilaterals (three is OK); The parallelogram has a right angle; The parallelograms are equal in length.

Square: four sides are equal and have four right angles (three right angles are fine); The diagonal line on the base of the rectangle is perpendicular; The diamond is equal on the diagonal.

This is relatively basic.

There is a set of quadrilaterals with opposite sides parallel to each other that are trapezoidal;

In a trapezoid, a group of opposites (two waists) that are not parallel are equal, that is, an isosceles trapezoid;

A quadrilateral with two pairs of opposite sides parallel is a parallelogram;

In a parallelogram, the four sides are equal, and the inner angles are not at right angles, is a diamond;

In a parallelogram, the four sides are equal and the inner angles are all right angles.

A parallelogram is rectangular when two sets of opposite sides are not equal and the inner angles are both right angles.

This is only a general method of determination, except for special ones.

The answer is.

The isotope angles are equal, and the two straight lines are parallel.

The inner staggered angles are equal, and the two straight lines are parallel.

The inner angles of the same side are complementary, and the two straight lines are parallel.

The two straight lines are parallel and the isotope angles are equal.

The two lines are parallel and the inner misalignment angles are equal.

The two straight lines are parallel and complementary to the side inner angles.

SAS) has two sides and their angles correspond to two triangles congruent asa) there are two angles and their intersections correspond to two triangles congruence (sss) there are three sides corresponding to two equal triangles congruence hl) there are hypotenuse and one right-angled side correspond to two equal right-angled triangles congruence In a right-angled triangle, if an acute angle is equal to 30°, then the right-angled side it is opposite is equal to half of the hypotenuse.

Pythagorean theorem The sum of the squares of the two right-angled sides a and b of a right triangle is equal to the square of the hypotenuse c, i.e., a 2 + b 2 = c 2

Parallelogram property theorem 1 Parallelogram diagonal equality parallelogram property theorem 2 Parallelogram opposites are equal and parallelogram property theorem 3 Parallelogram diagonal bipolar division of parallelogram determination theorem 1 Two sets of quadrilaterals with equal diagonal diagonals are parallelogram Parallelogram decision theorem 2 Two sets of quadrilaterals with equal opposite sides are parallelogram Parallelogram determination theorem 3 Quadrilateral diagonal bisect is parallelogram Parallelogram determination theorem 4 A set of quadrilaterals with parallel and equal opposite sides is a parallelogram and rectangular property theorem1 All four corners of a rectangle are right angles.

Rectangle property theorem 2 The diagonal lines of the rectangle are equal.

Rectangle Decision Theorem 1 A parallelogram with an angle that is at right angles is a rectangular rectangular decision theorem 2 A parallelogram with equal diagonal lines is a rectangular square property theorem 1 The four corners of a square are right angles and all four sides are equal Square property theorem 2 The two diagonals of a square are equal and bisected perpendicular to each other, and each diagonal divides a set of diagonals.

Rhomboid Properties Theorem 1 The four sides of a rhomboid are all equal.

Rhomboid properties theorem 2 The diagonals of a rhombus are perpendicular to each other.

Rhomboid area = half of the diagonal product, i.e. s = (a b) 2 Rhomboid Decision Theorem 1 A quadrilateral with all four sides equal is a rhombus.

Rhombic Decision Theorem 2 A parallelogram with diagonal perpendicular lines to each other is a rhombus, and Rhombus Decision Theorem 3 is a parallelogram with a symmetry axis figure, and a parallelogram is a rhombus.

The opposite sides of the parallelogram are parallel and equal or the corresponding sides are parallel to each other;

A trapezoid is rated as having opposite sides parallel to the other side that is not parallel.

Isosceles trapezoidal is a trapezoidal with an equal waist of trapezoidal;

A rhombus is a parallelogram with equal quadrilaterals;

A square is a rectangle with four equal sides;

The rectangle is a parallelogram with an internal angle of 90°.

Proof: E and F are the midpoints of AB and AC.

EF Block DH

EF≠DH Douxin quadrilateral defh is trapezoidal.

D and E are the midpoints of BC and AB, respectively.

de=1/2ac

HF is the midline of the hypotenuse of RT AHC.

hf=1/2acdefh

The quadrilateral defh is an isosceles trapezoidal balance wheel.