Triangle Inequality and Triangle Sum with Algebra

On the Unit 4 Test:

I can determine if 3 side lengths can make a triangle.

I can use the triangle inequality to give a range of possible lengths for a 3rd side of a triangle.

I can use the Triangle Angle Sum Theorem to find the angles in a triangle with Algebra.

Test Taking Strategies:

Read the problem carefully, twice, and define unfamiliar words.

Pretend it is an easier problem to find a strategy.

Use resources like notes and calculator tools.

Multiple Choice

The sum of the lengths of any two sides of a triangle is _____ than the third side

• less

• greater

• equal

Multiple Choice

Does the sides 8, 9, 10 make a triangle?

• yes

• no

Multiple Choice

Does the sides 1, 1, 2 make a triangle?

• yes

• no

Multiple Choice

Does the sides 6, 9, 8make a triangle?

• yes

• no

Multiple Choice

The lengths of two sides are given (8, 5). What are the possible length of the third side? Between what two numbers

• Between 5 and 8

• Between 3 and 13

• Between 3 and 5

• Between 5 and 13

Multiple Choice

The lengths of two sides are given (4, 13). What are the possible length of the third side? Between what two numbers

• Between 9 and 17

• Between 0 and 13

• Between 4 and 13

Multiple Choice

The lengths of two sides are given (9, 2). What are the possible length of the third side? Between what two numbers

• Between 0 and 2

• Between 2 and 9

• Between 7 and 11

Math Response

Simplify:

2x+3x+4x

Type answer here

Correct Answer: 9x

Deg^°

Rad

Math Response

Solve:

9x = 180

Type answer here

Correct Answer: 20

Deg^°

Rad

Multiple Choice

Simplify:

x - 20 + 3x + 3 + 2x -7

• 21x

• 5x -24

• 6x - 24

• 6x - 30

Math Response

Solve:

6x - 24 = 180

Type answer here

Correct Answer: 34

Deg^°

Rad

Multiple Choice

Solve the equation x+10+x+20+x+30=180

• 30

• 10

• 20

• 40

Open Ended

Three angles in a triangle are x, 5x, and 60. Write an equation you could use to solve for x.