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.
mA  mB  90
0
A
B
Examples
Examples with Algebra
1)
2)
Try These
1.)
3.)
x
40
2x
105
2.)
45
x
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.