Warm Up Using a compass, create one of each of the following: Duplicate an angle: Construct a...
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Transcript of Warm Up Using a compass, create one of each of the following: Duplicate an angle: Construct a...
Warm UpUsing a compass, create one of each of the following:
Duplicate an angle:
Construct a perpendicular bisector:
Construct a perpendicular to a line from a point:
3.4 Constructing an Angle Bisector
Method 1: FoldingStep 1: Using the patty paper, create your own
angle using a straightedge.Step 2: Fold the patty paper so that the two legs lie
on top of one another.Step 3: Draw a line down the crease
This is our angle bisector.
3.4 Constructing an Angle Bisector
Method 2: Using a compassStep 1: Put the point of the compass on the vertex
of the angle given and create two intersection points with the legs of the angle.
Step 2: With these two intersections do the same steps as you would for perpendicular bisector
Step 3: What observations can you make from this?
Conjecture C-7: Shortest Distance ConjectureThe shortest distance from a point to a line is
measured along the ______________ from the point to the line.
Conjecture C-8: Angle Bisector ConjectureIf a point is on the bisector of an angle, then it is
_____________ from the sides of the angle.
4.4 Congruence Shortcuts
How many parts do we need congruent for both triangles to be congruent?
6 parts?5 parts? 4 parts?3 parts?2 parts?1 parts?0 parts?
Combinations of three
(SSS) Side – Side – Side(SAS) Side – Angle – Side(ASA) Angle – Side – Angle (SAA) Side – Angle – Angle (SSA) Side – Side – Angle (AAA) Angle – Angle – Angle
SSS InvestigationThe length of each leg will be 2 inches, 3 inches and 4 inches
Instructions:1. Pick a length and use a straightedge to create this length near the
bottom of the paper. (to make sure we have enough room for the triangle)
2. Pick another length and measure the compass to this length.3. Put the point of the compass on an endpoint of your original line
and create a very large arc.4. Pick the last length and measure the compass to this length.5. Put the point of the compass on the other endpoint of your original
line and create a very large arc.6. The intersection of the two arcs will be the third point of your
triangle.7. Draw your triangle.8. Check to make sure the three legs of the triangle are actually 2,3,
and 4 inches.9. Cut out the triangle.
Conjecture C-23: SSS Congruence ConjectureIf the three sides of one triangle are congruent
to the three sides of another triangle, then ____________.
Conjecture C-24
Conjecture C-24: SAS Congruence ConjectureIf two sides and the included angle of one
triangle are congruent to two sides and the included angle of another triangle, then ______________.
SAS Investigation
The length of the two legs will be 2 and 4 inches, the angle will be 40 degrees
Instructions:1. Create your angle of 40 degrees using your protractor2. From the vertex measure a length of 2 or 4 inches along one of the
legs.3. From the vertex measure the other length along the other leg
We now have a 40 degree angle with legs of 2 and 4 inches.5. Using a straightedge and the endpoints of the legs create the third side
of the triangle.5. Cut out the triangle.6. Compare with three other triangles.