Mechanical Drawing
Lesson 5
Geometric Construction
Created By Kristi Mixon
Geometric Construction
•
Bisecting a line
•
Bisecting an angle
•
Drawing a circle through 3
random points
Bisecting a Line
A
B
Step 1: Place your compass
point at Point A and
draw and arc.
Bisecting a line
A
B
Step 2: Place your compass
at Point B, and draw
another arc. You should
now have two arcs that
intersect at two points:
C
&
D
C
D
Bisecting a line
A
B
C
D
Step 3: Draw a straight
line connecting Points
C
&
D
.
This line will divide line AB exactly
in half
Next
Bisecting an angle
A
B
C
Step 1: Place your compass
at point b, the vertex of angle
ABC, and draw an arc that
intersects line AB and line BC.
Bisecting an angle
A
B
C
Step 2: Place your compass needle
at point D, and draw another arc.
D
Bisecting an angle
A
B
C
D
E
Step 3: Place your compass
needle at point E, and draw
another arc, which will interest
the other arc drawn in step 2.
A
B
C
D
E
Bisecting an angle
Step 4: Draw a straight line
connecting point B and point F.
This line will divide angle ABC
exactly in half.
F
Next
Draw a circle from 3 random points
•
Step 1: Select 3
points in space that
do not form a straight
line. Label them point
A, B, and C.
A
B
C
Drawing a circle from 3 random points
•
Step 2: Connect the 3
points forming 2 line
segments, AB and BC.
A
B
C
Drawing a circle from 3 random points
•
Step 3: Bisect each
line segment. Draw
each line bisector so
they cross each other.
•
We will label the
intersection of the
bisectors point O
A
B
C
O
Drawing a Circle From 3 Random Points
•
Step 4: Using your
compass, place the
needle at point O and
the lead at one of the
other points.
•
As you draw the
circle, your compass
should pass through
each point
.
B
A
C
O
Needle point
Compass Lead
Next