Parallelism

Question 1

Triangle inequality Theorem

Answer 1

The length of any of the sides of a triangle must be shorter than the lengths of the other two sides added together.

Question 2

Concurrence

Answer 2

Three or more lines meet at a single point.

Question 3

Medians

Answer 3

Lines draw from the vertices that bisect the opposite side.

Question 4

Centroid

Answer 4

Point where three median lines are concurrent. Also center of mass.

Question 5

Altitude

Answer 5

Perpendicular line segments drawn from the vertex to the opposite side.

Question 6

Orthocenter

Answer 6

Where three altitude lines are concurrent. This point does not need to be inside the triangle.

Question 7

Angle Bisectors

Answer 7

Lines draw from the angle that splits an angle in half.

Question 8

Incenter

Answer 8

Point where the three angle bisectors are concurrent. Works in an acute triangle in which all angles less then 90 degrees. Always meets inside the triangle.

Question 9

Exterior Angle

Answer 9

The measurement between the shape and each line segment when you stretch it out past its shape. However many sides it has is how many exterior angles it has.
Exterior Angle=360/n

Question 10

Interior angle

Answer 10

Supplementary angle to the exterior Angle.

Interior angle=180-360/n

Interior angle=(n-2)*180/n

Question 11

Circumcenter

Answer 11

The point where three perpendicular bisectors are concurrent. The circle touches all three vertices and is outside the triangle.

Question 12

30 60 90 right triangles

Answer 12

Short side: a

Second side: aroot(3)

Hypotenuse: 2a