Perpendicular Bisectors
Angle Bisectors
Midsegments
Triangle Inequalities
Proofs & Properties
100

This line forms a 90-degree angle with a triangle's side and divides it into two equal parts.



What is a perpendicular bisector?

100

A point on an angle bisector has this relationship to the rays of the angle.


What is equidistant?

100

This segment connects the midpoints of two sides of a triangle.


What is a midsegment?

100

In a triangle, the sum of any two sides must have this relationship to the third side.


What is greater than?

100

This type of proof shows a statement is true by proving its opposite leads to a contradiction.


What is an indirect proof?

200

The perpendicular bisector of a triangle's side contains all points with this relationship to the endpoints.

 

What is equidistant?

200

When the angle bisector of a right angle divides it, each new angle measures this.


What is 45 degrees?

200

A midsegment is always this fraction of the parallel side of a triangle.


What is one-half?

200

If one angle in a triangle is larger than another angle, this is true about their opposite sides.



What is the side opposite the larger angle is longer?

200

A midsegment triangle has this relationship to the original triangle's area.


What is one-fourth?

300

The equation of a perpendicular bisector must pass through this point of the line segment.

What is the midpoint?

300

This type of triangle is formed when an angle bisector creates equal angles.

What are congruent triangles?

300

When all midsegments are drawn in a triangle, this special triangle is formed.

What is a midsegment triangle?

300

If a, b, and c are sides of a triangle, this inequality must be true.

What is a+b>c?

300

When proving triangle inequalities, this principle is often used to show one side must be longer than another.

What is the transitive property of inequalities?

400

In an isosceles triangle, the perpendicular bisector of the base also serves as this.

 

What is the altitude and median?

400

The angle bisector of an angle in a triangle divides the opposite side in this ratio.


What is proportional to the lengths of the adjacent sides?

400

A midsegment of a triangle has this relationship to the third side of the triangle.

What is parallel?

400

In a triangle, this side is always opposite to the largest angle.


What is the longest side?

400

When proving two triangles are congruent indirectly, this is often the first step.

What is assume the triangles are not congruent?

500

The three perpendicular bisectors of a triangle's sides intersect at this point.

What is the circumcenter?

500

The three angle bisectors of a triangle intersect at this point.

What is the incenter?

500

When all three midsegments are drawn, they divide the original triangle into this many similar triangles.

What is four similar triangles?

500

If a, b, and c are sides of a triangle where a>b>c, then their corresponding angles A, B, and C must have this relationship.

What is A>B>C?

500

In a proof by contradiction involving parallel lines cut by a transversal, this pair of angles is crucial.

What are corresponding angles?

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