Do Now

1.

Draw a right triangle. Label the hypotenuse and legs.

2.

Label the side lengths of this triangle with the following lengths: 20, 37.5, and 42.5.

3.

Do these side lengths create a right triangle? Show your work.

10.1: Triangles: Day 2

Objective: Solve problems involving triangles Homework: 10.1 Practice Worksheet- Classifying Triangles

A triangle can be classified by its sides and by its angles.

Classifying by sides

Equilateral: All 3 sides are congruent Isosceles: 2 sides are congruent Scalene: No sides are congruent

Examples

Classification by angles Acute: All 3 angles less than 90 degrees Obtuse: One angle is greater than 90 degrees Right: One angle is exactly 90 degrees Equiangular: All 3 angles are congruent

Examples

Practice: Classify the triangle by its sides and angles.

1.) 2.) 3.) 4.)

Practice: Classify the triangle by its sides and angles.

Do-Now

10.1: Triangles: Day 3

Objective: identify angle measures of triangles Homework: 10.1 Practice Worksheet- Finding Angle Measures of Triangles

Finding Angle Measures

Interior angles of a triangle add up to equal 180  .

Examples

Acute angles of a right triangle are complementary.

A

m



A



m



B

 90 0 B

Examples

1)

Examples with Algebra

2)

Try These 1.) x 40 2.) 45 105 x 3.) 2x x 3x

Do Now

10.1: Triangles: Day 4

Objective: use perimeter to find missing side

lengths of triangles

Homework: 10.1 Practice A Worksheet- Using Perimeter to Find Missing Side Lengths of Triangles

Using Perimeter to Find Side Lengths

Find the unknown side length of the triangle given the perimeter P. Then classify the triangle by its side lengths.

Examples

1. The ratio of the angle measures of a triangle is 3 : 4 : 5. Find the angle measures. Then classify the triangle by its angle measures.

2. The ratio of the angle measures of a triangle is 7 : 12 : 17. Find the angle measures. Then classify the triangle by its angle measures.