Median ~ Hinge Theorem

_____(0-10 pts.) Describe what a median is. Explain what a centroid is. Explain the concurrency of medians of a triangle theorem. Give at least 3 examples of each.

Describe what a median is. Median: Is a line drawn from one vertex of a triangle to the midpoint of the opposite side. Every triangle has three medians. Medians are concurrent

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Explain the concurrency of medians of a triangle theorem. The point of concurrency of the medians is called the centroid. (Where all median meet.) Centroid Theorem: on every median of any triangle, the distance from the vertex to the centroid is double the distance from the centroid to the midpoint of the opposite side.

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_____(0-10 pts. ) Describe what an altitude of a triangle is _____(0-10 pts.) Describe what an altitude of a triangle is. Explain what an orthocenter is. Explain the concurrency of altitudes of a triangle theorem. Give at least 3 examples.

Describe what an altitude of a triangle is. Altitude: A line from the vertex perpendicular to the opposite side. An altitude can be inside, outside, or on the triangle.

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Explain what an orthocenter is. Orthocenter: The point of congruency for the 3 altitudes. (where all altitudes meet) The orthocenter of an acute triangle is inside the triangle. The orthocenter of a right triangle is on the vertex of the 90 degrees angle. The orthocenter of an obtuse triangle is on the outside of the triangle.

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Explain the concurrency of altitudes of a triangle theorem. That the three altitudes of any triangle are concurrent. (this point of concurrency is called orthocenter)

_____(0-10 pts. ) Describe what a midsegment is _____(0-10 pts.) Describe what a midsegment is. Explain the midsegment theorem. Give at least 3 examples.

Describe what a midsegment is. A segment that joins any two midpoints of a triangle. The midsegment is parallel to the opposite side, and it is half as long as the opposite side.

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Explain the midsegment theorem. A midsegment of a triangle is parallel to a side of the triangle. Its length is the half the length of that side.

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_____(0-10 pts.) Describe the relationship between the longer and shorter sides of a triangle and their opposite angles. Give at least 3 examples.

Angle-Side Relationships in Triangles The side that is opposite the largest angle will always be the longest side. The side that is opposite the smallest angle will be always the shortest side.

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_____(0-10 pts. ) Describe the exterior angle inequality _____(0-10 pts.) Describe the exterior angle inequality. Give at least 3 examples.

Exterior angle inequality. An exterior angle of a triangle that is greater than either of the non-adjacent interior angles.

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_____(0-10 pts. ) Describe the triangle inequality _____(0-10 pts.) Describe the triangle inequality. Give at least 3 examples.

Triangle inequality In every triangle the sum of the lengths of the two shorter sides must always be longer than the 3rd side.

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_____(0-10 pts. ) Describe how to write an indirect proof _____(0-10 pts.) Describe how to write an indirect proof. Give at least 3 examples.

Indirect Proof You begin by assuming that the conclusion is false. Then show that this assumption leads to a contradiction. Also called proof by contradiction.

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_____(0-10 pts. ) Describe the hinge theorem and its converse _____(0-10 pts.) Describe the hinge theorem and its converse. Give at least 3 examples.

Hinge theorem and its converse. If the two sides of two triangles are congruent but the third side is not congruent, then the triangle with the longer side, will have a larger included angle. Converse: If two sides of one triangle are congruent to two sides of another triangle and the tird sides are not congruent, then the larger included angle is across from the longer third side.

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