G.5 Triangle Inequalities (2016).notebook
November 04, 2016
Do Now:
1. Draw a triangle (using a straight edge) in the middle of your
next blank page. Find (and label) the length of each side, and the
measure of each angle.
2. Color or highlight the longest side and the biggest angle using
the same color
3. Use a different color, highlight the shortest side and the
smallest angle.
4. Underneath, write a conjecture about the relationship between
the sides and the angles.
G.5 Triangle Inequalities
Learning Target - by the end of class, given limited information
about a triangle, I will be able to determine a missing angle or
the range of possible values for the length of a side, or be able
to sort angles or sides from smallest and biggest. I will do this
by taking notes and working a series of problems as a class and
individualy before completing an exit ticket with 3 of 4 correct.
SOL - G.5
Homework - p.329-330, #9, 10, 15, 19, 27, 34, 35
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
The longest side is always opposite the biggest angle in a triangle. Conversely, the biggest angle is always opposite the longest side. B
100
5"
4"
30
50
A
Triangle Types
Scalene
Right
C
6"
Isoceles
Equilateral
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
Put the sides in order from longest
to shortest.
Put the angles in order
from smallest to biggest
L
A
40
7"
6"
C
5"
100
M
B
50
Draw a triangle with sides of lengths 6", 3" and 2".
Leave picture covered while students complete activity
3"
2"
6"
N
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
Triangle Inequality Theorem - the length of any side of a triangle
will be less than the sum of the other two sides
which combination of side lengths could make a triangle?
Technique ­ circle the largest number. The other two numbers should add to MORE than the circled number.
3, 4, 5
6, 9, 3
10, 4, 5
Determine which of the "triplets" could make a triangle.
Ex: 8, 10, 14
3, 4, 8
14
10
8
5, 6, 11
22, 18, 40
40, 60, 90
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
Range of values for the third side of a triangle
6"
Find the range of possible values for the third side of the triangles.
3
5
y
12
7
x
____ < x < _____
7
x
5
____ < y < _____
9
9
x
G.5 Triangle Inequalities (2016).notebook
7
x
5
____ < x < _____
November 04, 2016
9
9
x
____ < x < _____
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
D
G.5 Triangle Inequalities (2016).notebook
November 04, 2016
G.5 Triangle Inequalities
Learning Target - by the end of class, given limited information
about a triangle, I will be able to determine a missing angle or
the range of possible values for the length of a side, or be able
to sort angles or sides from smallest and biggest. I will do this
by taking notes and working a series of problems as a class and
individualy before completing an exit ticket with 3 of 4 correct.
SOL - G.5
Homework - p.329-330, #9, 10, 15, 19, 27, 34, 35
Exit ticket
1. Which combos make a triangle?
a) 5, 6, 7
b) 1, 2, 3
c) 11, 12, 13
d) 5, 6, 12
3. Order the sides longest to shortest.
L
2. Order the angles smallest to largest.
R
7"
T
9"
10"
S
4. Find the range of values for the missing side.
55
12
15
N
60
65
M
x
G.5 Triangle Inequalities (2016).notebook
November 04, 2016