Triangle Unit

Question 1

How do you name a triangle?

Answer 1

With the symbol for triangle (∆) and the 3 vertices in any order

Question 2

What do we call a triangle with no sides congruent?

Answer 2

Scalene

Question 3

What do we call a triangle with 2 congruent sides?

Answer 3

Isosceles

Question 4

What do we call a triangle with all 3 sides congruent?

Answer 4

Equilateral

Question 5

An equilateral triangle is automatically what?

Answer 5

Equiangular

Question 6

What does equiangular mean?

Answer 6

All the angles are congruent

Question 7

What do we know about the angles in an equilateral triangle?

Answer 7

All have measure 60º

Question 8

What do we know about the angles in an isosceles triangle?

Answer 8

Base angles are congruent

Question 9

The angle measures in any triangle add up to what?

Answer 9

180º

Question 10

What are the classifications of triangles based on its angles?

Answer 10

Acute, right, obtuse

Question 11

Define obtuse triangle.

Answer 11

A triangle with an obtuse angle

Question 12

Define right triangle.

Answer 12

A triangle with a right angle

Question 13

Define acute triangle.

Answer 13

A triangle with all acute angles

Question 14

The acute angles in a right triangle are what?

Answer 14

Complementary

Question 15

How do you draw an exterior angle?

Answer 15

Extend one side of the triangle. The angle is made by the extension and side of the triangle

Question 16

The measure of the exterior angle is the same as what?

Answer 16

The sum of the measures of the remote interior angles

Question 17

What is a median of a triangle?

Answer 17

A line segment from the vertex to the midpoint of the opposite side

Question 18

What should you mark whenever you have a median?

Answer 18

Congruent segments

Question 19

What is an altitude of a triangle?

Answer 19

A line segment from a vertex that is perpendicular to the opposite side

Question 20

What should you mark whenever you have an altitude?

Answer 20

Right angles

Question 21

What is special about the altitudes in a right triangle?

Answer 21

The 2 legs are also altitudes

Question 22

What is special about the altitudes in an obtuse triangle?

Answer 22

The 2 altitudes from the acute angles go outside the triangle

Question 23

What is special about the altitude from the vertex angle in an isosceles triangle?

Answer 23

It is also a median and angle bisector

Question 24

What is special about the altitudes in an equilateral triangle?

Answer 24

They are all also medians and angle bisectors

Question 25

Define a midsegment of a triangle.

Answer 25

A line segment connecting the midpoints of 2 sides of the triangle

Question 26

What are the two properties for a midsegment of a triangle?

Answer 26

It is parallel to the 3rd side and half the length of the 3rd side

Question 27

What should you mark when you have a midsegment?

Answer 27

Parallel lines, congruent corresponding angles from the parallel lines, congruent segments from the midpoints

Question 28

What is the definition of two congruent triangles?

Answer 28

Two triangles with all the corresponding sides congruent and all the corresponding angles congruent

Question 29

What are the methods to prove any 2 triangles congruent?

Answer 29

SSS, SAS, ASA, AAS

Question 30

What are the extra methods to prove two right triangles congruent?

Answer 30

LL, LA, HA, HL

Question 31

Which of the four methods of proving right triangles congruent is most important, and why?

Answer 31

HL because it is the only method that does not correspond to one of the methods that can prove ALL triangles congruent

Question 32

What does CPCTC mean?

Answer 32

Corresponding Parts of Congruent Triangles are Congruent

Question 33

In a triangle, which angle must be the largest?

Answer 33

The one opposite the largest side

Question 34

In a triangle, which angle must be the smallest?

Answer 34

The one opposite the smallest side

Question 35

In a triangle, which side must be the largest?

Answer 35

The one opposite the largest angle

Question 36

In a triangle, which side must be the smallest?

Answer 36

The one opposite the smallest angle

Question 37

The sum of the lengths of the smallest 2 sides of a triangle must be what?

Answer 37

Greater than the length of the 3rd side

Question 38

If 2 sides of a triangle have lengths x and y, what are all the possible lengths for the 3rd side?

Answer 38

| x – y | < 3rd side < x + y | x – y | < 3rd side < x + y