4.1-4.2

Question 1

congruent triangles

Answer 1

two triangles are congruent if there is a correspondence between their angles and sides such that corresponding angles are congruent and corresponding sides are congruent.

Question 2

equilateral triangle

Answer 2

an equilateral triangle has 3 congruent sides.

Question 3

isosceles triangle

Answer 3

an isosceles triangle has at least two congruent sides.

Question 4

scalene triangle

Answer 4

a scalene triangle is a triangle that has no congruent sides.

Question 5

vertex

Answer 5

a vertex of a polygon is a common endpoint of two of it’s sides.

Question 6

Opposite side

Answer 6

(un official. refer to theorems notebook for example and diagram) a side opposite an angle of a triangle. (book says in triangle ABC, side BC is opposite angle A).

Question 7

adjacent sides

Answer 7

in a triangle or other polygon, two sides that share a common vertex are adjacent sides.

Question 8

right triangle

Answer 8

a right triangle is a triangle with exactly 1 right angle

Question 9

legs of a right triangle

Answer 9

In a right triangle, the sides adjacent to the right angle are the legs of the triangle.

Question 10

hypotenuse

Answer 10

in a right triangle, the side opposite the right angle is the hypotenuse.

Question 11

acute triangle

Answer 11

an acute triangle has three acute angles.

Question 12

equiangular triangle

Answer 12

an equiangular triangle has three congruent angles, each with a measure of 60°

Question 13

obtuse triangle

Answer 13

an obtuse triangle has exactly one obtuse angle.

Question 14

legs of an isosceles triangle

Answer 14

In an isosceles triangle with 2 congruent sides, the congruent sides are called legs.

Question 15

base of an isosceles triangle

Answer 15

In an isosceles triangle with 2 congruent sides, the third side is called the base of the isosceles triangle.

Question 16

properties of congruent triangles

Answer 16

1. every triangle is congruent to itself
2. If triangle ABC is congruent to triangle PQR, then triangle PQR is congruent to triangle ABC
3. If triangle ABC is congruent to triangle PQR and triangle PQR is congruent to triangle TUV, then triangle ABC is congruent to triangle TUV

Question 17

Interior angles of a triangle

Answer 17

the original three angles in a triangle.

Question 18

exterior angles of a triangle

Answer 18

when the sides of a triangle are extended, the angles that are adjacent to the interior angles of a triangle are the exterior angles. each vertex has a pair of exterior angles

Question 19

triangle sum theorem

Answer 19

the sum of the measures of the interior angles of a triangle is 180°

Question 20

third angles theorem

Answer 20

if 2 angles of 1 triangle are congruent to 2 angles of a second triangle, then the third angles are also congruent.

Question 21

theorem 4.4

Answer 21

the acute angles of a right triangle are complementary

Question 22

exterior angles theorem

Answer 22

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

Question 23

exterior angles inequality theorem

Answer 23

the measure of an exterior angle of a triangle is greater than the measure of either of the two remote interior angles.