Plane geometry correlation formula and its common auxiliary lines in junior high school（初中平面几何相关公式及其常用辅助线）Related formulas of plane geometry in junior high school1 there is only one line at two points, and the line between 2 and two is the shortest3 the same angle or equiangular supplementary 4 equal angle or the angle equal to the same.5 having only one line and perpendicular to the known line6, the line outside a point and the line on all points connected by the line, the vertical line segment is the shortest7 parallel axioms follow a point outside the straight line and have only one line in parallel with the line8 if the two lines are parallel to the third lines, the two lines are parallel to each other9 corresponding angles are equal, two parallel straight lines parallel 10 alternate angles equal to two11 complementary interior angles on the same side, two parallel lines 12 two parallel lines, corresponding angles are equal13 the two parallel lines, 14 parallel lines two alternate angles equal, complementary interior angles on the same sideThe sum of 15 sides of a triangle is greater than third16 infer that the difference between the sides of a triangle is less than third17 triangle triangle sum theorem three angles and equal to 180 degrees18 inference 1 the two acute angles of right triangle overlap each other19 a corollary of a triangle is equal to the 2 corners and two angles it is adjacent and20 a corollary of a triangle with 3 corners than any one and it is not adjacent.The corresponding sides of 21 congruent triangles and equal angles22 edges, angles, axioms, two sides, and their angles equal to the same triangle23 corner corner axioms of two triangles congruent corners and their edges corresponding to the equal24 that had two horns and one angle on the side corresponding to the equal two congruent trianglesA congruence of two triangles having three equal sides on the 25 side26, the bevel, the right side, the axiom has a bevel and a right angle corresponding to the two right triangle congruent27 theorem 1 the distance between points on the bisector of an angle to the sides of this angle is equalThe point at which the distance between 2 and 28 angles is the same as in the bisector of this angleThe bisector of 29 angles is the set of all points equal to the two sides of the angleTwo and 30 are equal isosceles triangle isosceles triangle theorem31 infer that the bisector of the 1 isosceles triangle vertex is equal to the base and perpendicular to the base32 The isosceles triangle, the bisector, the middle line on the bottom edge and the height coincide with each other33 corollary 3 equilateral triangles whose angles are equal, and each angle equal to 60 degrees34 the decision theorem of isosceles triangle, if a triangle has two angles equal, then the two angles are equal to the sides (equal angles, equal sides)35 corollary 1 three angles are equal triangle is an equilateral triangle36 corollary 2 an isosceles triangle with an angle equal to 60 degrees is an equilateral triangle37 in a right triangle, if an acute angle is equal to 30 degrees, the right angle of it is equal to half of the slope38 the center line on the bevel of a right triangle is equal to half of the bevelThe point at which the two ends of the line of the line of division are equal to the 39 ends of the lineA point equal to the distance between two endpoints of 40 inverse theorem and a line segment, in the vertical bisector of the lineThe vertical bisector of a 41 line segment can be considered as a set of all points equal to the distance between points at the end of a line segment42 theorem 1 the two graphs of a straight line symmetry are congruent forms43 theorem 2 if two graphs are symmetrical about a straight line, then the symmetry axis is the vertical bisector of the corresponding line44 theorems 3. Two graphs are symmetrical about a straight line, if their corresponding line or extension line intersects, then the intersection point is on the symmetry axisThe 45 inverse theorem is that if the corresponding points of the two graphs are vertically divided by the same line, then the two figures are symmetrical about the line46 Pythagorean theorem of right triangle two right angle sides a, b square, and the square is equal to the hypotenuse C, a+b=c47 the Pythagorean theorem and inverse theorem of a, if the three side of triangle B, C a+b=c, then the triangle is a right triangleIn theorem 48 quadrilateral and equal to 360 degrees49 quadrilateral corners and is equal to 360 degreesIn the 50 polygon sum theorem n edge shape and is equal to (n-2) * 180 degrees51 any inference multilateral angle and equal to 360 degreesThe property theorem of 52 parallelogram; the diagonal equality of 1 parallelogramThe property theorem of 53 parallelogram; the e