Geometry Topic 2 Lines Angles and Triangles Table

Geometry Topic 2 Lines, Angles, and Triangles

Table of Contents • Recommended Instructional Design and Planning Continuum. . . . Slide 3 • Vocabulary …………………………………. . Slides 4 – 22 • Reporting Category Practice Items …………………. Slides 23 - 51

Vocabulary

Mathematically Speaking! Choose 3 -4 vocabulary words for the day. Throughout the lesson, as students respond to your questions or are presenting a problem on the board, mark a tally when a vocabulary word is used accurately. This can be turned into a competition among groups or between periods. Examples of accuracy • vertical angles vs opposite angles • hypotenuse vs the long side • congruent vs same

Vertical angles – the non adjacent angles formed by two intersecting lines.

Transversal – a line that intersects at least two other lines.

Parallel Lines

Indirect proof – a proof in which the statement to be proved is assumed to be false and a contradiction is shown.

Hypotenuse – the side opposite the right angle in a right triangle.

Interior angle – an angle formed by two sides of a polygon with a common vertex.

Auxiliary line – a line drawn in a figure to aid in a proof.

Exterior angle – an angle formed by one side of a polygon and the extension of an adjacent side.

Isosceles triangle – a triangle with at least two congruent sides.

Equilateral triangle – a triangle with three congruent sides. Equiangular triangle – a triangle with three congruent angles.

Triangle Inequality Theorem - The sum of the lengths of any two sides of a triangle is greater than the length of the third side. Example: AB + BC > AC AC + BC > AB AB + AC > BC

Congruent Triangles

SSS Triangle Congruence Postulate

SAS Triangle Congruence Postulate

ASA Triangle Congruence Postulate

AAS Triangle Congruence Theorem

HL Right Triangle Congruence