Download Lesson 4.3 ADV - Advanced Geometry: 2(A)

Lesson 4.3:
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2.
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Homework Discussion
Isosceles Triangles
Triangle Inequalities
Exterior Angle Theorem
Warm Up #1 – 4.1 hw #10:
• Determine the value of each letter.
Warm Up #2:
• Determine the value of each letter.
Revisiting a Previous Problem:
(From the 3.4 Warm Up)
a) Use a compass and a ruler to construct a triangle with
side lengths of 6 cm, 8 cm, and 10 cm. What type of
triangle is this – classify by sides and angles.
b) Use a compass and a ruler to construct a triangle with
side lengths of 6 cm, 8 cm, and 18 cm. What type of
triangle is this – classify by sides and angles.
Triangle Inequalities:
Triangle Inequality Conjecture:
The sum of the lengths of any two sides of a triangle is __________ the
length of the third side.
• Investigation #2 – Use the handout to complete the investigation.
Side-Angle Inequality Conjecture:
In a triangle, if one side is longer than another side, then the angle
opposite the longer side is ___________________.
Practice #1:
• Determine whether it is possible to draw a triangle with
sides having the given measures. If possible, write yes.
If not possible, write no and make a sketch
demonstrating why it is not possible.
a) 3 cm, 4 cm, 5cm
b) 6 m, 9 m, 16 m
Practice #2:
• Use your new conjectures to arrange the
unknown measures in order from greatest
to least.
11
c
16
b
18
a
More Vocabulary:
• Interior vs. Exterior Angles with Triangles:
Investigation #3 - Sketchpad:
Practice #3:
• Use the exterior angle conjecture to find the
value of x.
Practice #4:
• Find the value of x. Then find the measure of
the exterior angle.
Practice #5:
• What’s wrong with this picture?
Homework:
• P. 218-220: 1, 3, 6, 7, 10, 13, 15-17, 20,
22
Challenge: