4.1.2 Angle Relationships in Triangles

Question 1

auxiliary line

Answer 1

is a line that is added to a figure to aid in a proof.

Question 2

corollary

Answer 2

is a theorem whose proof follows directly from another theorem.

Question 3

interior of a figure

Answer 3

is the set of all points inside the figure.

Question 4

exterior of a figure

Answer 4

is the set of all points outside the figure.

Question 5

interior angle

Answer 5

is formed by two sides of a polygon.

Question 6

exterior angle

Answer 6

is formed by one side of a polygon and the extension of an adjacent side.

Question 7

remote interior angle

Answer 7

each exterior angle has two remote interior angles. A remote interior angle is an interior angle that is not adjacent to the exterior angle.

Question 8

Triangle Sum Theorem

Answer 8

The sum of the angle measures of a triangle is 180°.

Question 9

Corollary

Answer 9

The acute angles of a right triangle are complementary.

Question 10

Corollary

Answer 10

The measure of each angle of an equiangular triangle is 60°.

Question 11

Exterior Angle Theorem

Answer 11

The measure of an exterior angle of a triangle is equal to the sum of the measures of its remote
interior angles.

Question 12

Third Angles Theorem

Answer 12

If two angles of one triangle are congruent to two angles of another triangle, then the third pair
of angles are congruent.