Chapter 5: Triangles

Question 1

A polygon is

Answer 1

a geometric figure whose sides are line segments

Question 2

A triangle is

Answer 2

a polygon that has three sides

Question 3

A scalene triangle has

Answer 3

no congruent (equal) sides

Question 4

An isosceles triangle has

Answer 4

at least two congruent (equal) sides

Question 5

An equilateral triangle has

Answer 5

all three congruent (equal) sides

Question 6

An acute triangle has

Answer 6

all three angles with measure of less than 90

Question 7

A right triangle has

Answer 7

one angle with a measure of 90

Question 8

obtuse triangle

Answer 8

has one angle with a measure of greater than 90

Question 9

Theorem 16: If two lines are parallel to a third line,

Answer 9

then the lines are parallel to each other

Question 10

Postulate 8: Through a given point not on a line,

Answer 10

exactly one line may be drawn parallel to the line

Question 11

Theorem 17: The sum of the measures of the angles of a triangle is

Answer 11

180

Question 12

Corollary 17.1: The acute angles of a right triangle are

Answer 12

complementary

Question 13

Corollary 17.2: The measure of each angle of an equiangular triangle is

Answer 13

60

Question 14

Corollary 17.3: If two angles of a triangle are congruent to two angles of another triangle,

Answer 14

then the remaining pair of angles is congruent

Question 15

Exterior Angle of a Polygon

Answer 15

an angle that forms a linear pair with one of the interior angles of the polygon

Question 16

An equiangular triangle has

Answer 16

all three angles with equal measures

Question 17

Theorem 18: Exterior Angle of a Triangle Theorem: The measure of an exterior angle of a triangle is equal to

Answer 17

the sum of the measures of the two remote interior angles

Question 18

Definition of Congruent Triangles:

Answer 18

If the vertices of two triangles can be paired in a correspondence so that all pairs of corresponding angles are congruent and all pairs of corresponding sides are congruent, then the triangles are congruent.

Question 19

Postulate 9: Side-Angle-Side Postulate: If the vertices of two triangles can be paired so that two sides and the included angle of one triangle are congruent to the corresponding parts of the second triangle,

Answer 19

then the two triangles are congruent

Question 20

Postulate 10: Angle-Side-Angle Postulate: If the vertices of two triangles can be paired so that the two angles and the included side of one triangle are congruent to the corresponding parts of the second triangle,

Answer 20

then the two triangles are congruent

Question 21

Theorem 19: Angle-Angle-Side Theorem: If the vertices of two triangles can be paired to that two angles and the side opposite one of the in one triangle are congruent to the corresponding parts of the second triangle,

Answer 21

then the two triangles are congruent

Question 29

Postulate 11: Hypotenuse-Leg Postulate: If the vertices of two right triangles can be paired so that the hypotenuse and leg of one of them are congruent to the corresponding parts of the second triangle, then

Answer 29

the two triangles are congruent

Question 30

Postulate 12: Side-Side-Side Postulate: If the vertices of two triangles can be paired so that three sides of one triangle are congruent to the corresponding sides of the second triangle, then

Answer 30

the two triangles are congruent