180 Section 2 Drafting Techniques and Skills
circumscribe the polygon outside a circle. The
Inscribed
option of the
Polygon
command is
used to inscribe a polygon within a circle. The
Circumscribed
option is used to circumscribe
a polygon about a circle. With each option, the
radius of the circle is entered after specifying
the number of sides. If you are constructing a
square and you know the length of the diago-
nal, you can use the
Inscribed
option.
1. The length of the diagonal (Line AC) is
given, Figure 6-28A.
2. Enter the
Polygon
command and specify
the number of sides as four.
3. Enter coordinates or pick a point on
screen to specify the center of the square.
4. Enter the
Inscribed
option. This allows
you to specify the distance between the
corners of the square. When prompted
for the radius of the circle, enter a length
equal to one-half the diagonal. If you
move the cursor, the square is drawn
dynamically on screen. Enter a radius
value or use direct distance entry,
Figure 6-28B.
5. After specifying the radius, the required
square is generated automatically,
Figure 6-28C. Note that the circle in
Figure 6-28B is shown for reference
purposes and is not actually drawn by
the
Polygon
command.
Construct a
Square with
the Length of the Diagonal
Given
CAD
Using a Compass and Triangle
(Manual Procedure)
1. The length of the diagonal (Line AC) is
given, Figure 6-27A.
2. With a radius (R
1
) equal to one-half the
diagonal, use a compass to construct a
circle, Figure 6-27B.
3. Using a 45° triangle, draw 45° diagonals
(Lines AC and DB) through the center of
the circle. The points where the diago-
nals intersect the circle become Points A,
B, C, and D.
4. Draw lines joining Points A and B, B and
C, C and D, and D and A. These lines
form the required square, Figure 6-27C.
Using the Polygon Command
(CAD Procedure)
When using the
Polygon
command,
instead of specifying a side length, you
can specify a radial distance that is used to
inscribe the polygon within a circle. You can
also specify a radial distance that is used to
Figure 6-27. Constructing a square when the diagonal length is known using a compass and a 45° triangle.
A C
A B
C D
R1
45–
A B
A B
C D
C
45–