2.4 Constructions: Constructing Angle Bisectors
During this lesson, we will:
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Paper fold an angle bisector to explore its properties
Construct an angle bisector
Construct an equilateral triangle
Construct/describe the construction of angles of different measures by duplicating angles
and bisecting angles
VOCABULARY
Recall: An angle bisector is a ray which has an endpoint
on the vertex of an angle and which divides the angle
into two ___________________________________.
INVESTIGATION: Paper-Folding an Angle Bisector
(Staple OR illustrate your paper-folded angle bisector here.)
CONJECTURE: If a point lies on the angle bisector of an angle, then it is
_________________________________ from the sides of the angle.
CONSTRUCTION: Angle Bisector
INVESTIGATION: Equilateral Triangle
___________________________________________
CONJECTURE: The measure of each angle of an equilateral triangle is _______.
CHECKING FOR UNDERSTANDING
C
Match each construction with its
diagram.
1. Angle bisector
2. Perpendicular
Bisector
3. 60 angle
4. Altitude
.
B
.
A
.
D
.
5. What construction produces a right angle? … a 45 angle?
6. What construction produces a 60 angle?...a 30 angle?
7. Complete the chart below:
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8. Use the chart above to help describe how to construct an angle with measure a.
135 and b. 15.