Math Angle Theorems

Theorem 1 vertical angles are equal.

Math angle theorems. This can be proved as follows. The measure of an exterior angle of a trianlge is equal to. If a transversal intersects two parallel lines then the alternate interior angles. If two triangles are similar the corresponding sides are in proportion.

The lines oa op and ob are equal radii of circle. The sum of the measures of the angles of a triangle is 180 theorem 4 3 exterior angle theorem. Theorem 3 if two lines are intersected by a transversal and if alternate angles are equal then the two lines are parallel. Theorem 2 in any triangle the sum of two interior angles is less than two right angles.

In the sketch below we have cat and bug. Mid segment theorem also called mid line. An included side is the side between two angles. If two angles of one triangle are congruent to two angles of a second triangle then the third angles of the triangles are congruent theorem 4 1 angle sum theorem.

Alternate exterior angles theorem. Theorem 4 2 third angle theorem. The end points are either end of a circle s diameter the apex point can be anywhere on the circumference. A the angle at the circumference subtended by a diameter is 90.

When two parallel lines are cut by a transversal then resulting alternate interior. Angle in a semicircle thales theorem an angle inscribed across a circle s diameter is always a right angle. Triangles and are isosceles. Some of the worksheets below are geometry postulates and theorems list with pictures ruler postulate angle addition postulate protractor postulate pythagorean theorem complementary angles supplementary angles congruent triangles legs of an isosceles triangle.

Asa theorem angle side angle the angle side angle postulate asa says triangles are congruent if any two angles and their included side are equal in the triangles. Learn vocabulary terms and more with flashcards games and other study tools. Alternate interior angles theorem. If a transversal intersects two parallel lines then the alternate exterior angles.

Start studying chapter 1 math test definitions and theorems. This is usually stated as the angle in a semicircle 90. If an angle of one triangle is congruent to the corresponding angle of another triangle and the lengths of the sides including these angles are in proportion the triangles are similar.