Chapter 6 Basic Geometric Constructions 195
Construct a Line
Tangent to a Circle
or Arc Using the Tangent
Object Snap
CAD
fies the task of drawing tangent objects. You fi
can draw a line tangent to a given circle by
using the Tangent object snap with the
Line
command. After entering the command and
specifying a first point at any location, select fi
the Tangent object snap and move the cursor
near the point of tangency on the circle. When
you pick, the tangent line is drawn automati-
cally. To draw a line tangent to a circle at a
specific point on the circle, use the following fi
procedure.
1. A line is to be drawn tangent to the
circle at the point of tangency (Point P),
Figure 6-46A.
Figure 6-46. Constructing a line tangent to a given circle. A—A line is to be drawn tangent to the circle at Point P.
B—A copy of the circle is made with its center point at Point P. C—Lines tangent to the two circles are drawn by
using the Tangent object snap. D—The tangent line is drawn between Point T1 and Point T3.
C
P
C
P
C
P
C
P
A B
C D
Copied
circle
Second
tangent
point
First
tangent
point
Tangent
line
T2
T2
T4
T3
T4
T3
T1
T1
2. Enter the
Copy
command and make a
copy of the circle, Figure 6-46B. Place the
center point of the new circle at Point P.
Using the Center object snap, select
Point C as the base point and Point P as
the second point.
3. Enter the
Line
command and use the
Tangent object snap to draw two separate
lines that are tangent to the two circles,
Figure 6-46C. To specify the first point fi
of the fi rst line, enter the Tangent object fi
snap and pick near the circle at Point T
1
.
To specify the second point, enter the
Tangent object snap again and pick near
the circle at Point T
2
. Repeat this step
with Point T
3
and Point T
4
T to draw the
second tangent line.
4. Enter the
Line
command and connect
Point T
1
to Point T
3
using the Endpoint
object snap. This is the required tangent
line, Figure 6-46D.