Math 1 March 5th

What you need today in class: Get a compass and protractor

Pick up a new warm-up sheet and a new packet

WARM-UP:

#1 Copy the diagram and label the measure of each angle (all 8)

133o

Special Lines in TrianglesName of Line Definition Picture or Construction

Angle Bisector

Perpendicular Segment Bisector

Altitude

Median

Special Lines in TrianglesName of Line Definition Picture or Construction

Angle Bisector Cuts an angle into two congruent angles

Perpendicular Segment Bisector

Altitude

Median

Special Lines in TrianglesName of Line Definition Picture or Construction

Angle Bisector Cuts an angle into two congruent angles

Perpendicular Segment Bisector

Cuts a segment into two congruent segments at a

90o angle

Altitude

Median

Special Lines in TrianglesName of Line Definition Picture or Construction

Angle Bisector Cuts an angle into two congruent angles

Perpendicular Segment Bisector

Cuts a segment into two congruent segments at a

90o angle

AltitudeHeight of a triangle;

Perpendicular from base to vertex

Median

Special Lines in TrianglesName of Line Definition Picture or Construction

Angle Bisector Cuts an angle into two congruent angles

Perpendicular Segment Bisector

Cuts a segment into two congruent segments at a

90o angle

AltitudeHeight of a triangle;

Segment drawn perpendicular from base to

vertex

MedianA segment from the

midpoint of a side to the opposite vertex

Place the compass point on the angle’s vertex.

Adjust the compass to a medium wide setting. The exact width is not important.

Without changing the compass width, draw an arc across each leg of the angle.

Place the compass on the point where one arc crosses a leg and draw an arc in the interior of the angle.

Without changing the compass width, repeat for the other leg so that the two arcs cross.

Use a straightedge to draw a line from the vertex to the point where the arcs cross.

Place the compass on one end of the line segment.

Set the compass width to approximately two thirds the line length. Actual width does not mater

Hold the compass in place and without changing the width , draw an arc above and below the line. (You can also draw it through the line)

Without changing the compass width, move the compass point to the other endpoint of the segment. Draw another arc above and below the line so that the arcs cross the first ones.

Using a straightedge, draw a line between the points where the arcs intersect.

Start with a line and point which is not on that line.

Place the compass on the given external point (R)

Set the compass width to approximately 50% more than the distance to the line. The exact width does not matter.

Draw an arc across the line on each side of “R”, making sure not to adjust the compass width in between.

At this point, you can adjust the compass width. From each point where the arcs intersect the segment, draw and arc below the line so that the arcs cross. Keep the width the same when drawing both of these arcs.

Using a straightedge, draw a line from point “R” to where the arcs intersect.