A plane has only two dimensions. Your layout is a

plane. This section gives methods of construction for

several plane figures.

Figure 14-18 shows the steps in drawing a triangle

with given lengths for its sides. The lengths for the

sides are shown in view A.

1. Draw one side of the triangle in the desired

position as the base line (view B).

perpendicular to a given line from a given point (refer

to fig. 14-9).

2. Adjust the dividers to the length of a second

side. Using one end of the base line as a center

for the point of the dividers, draw an arc (view

B).

Look at figure 14-20. Here, you can see how to

3. Adjust the dividers to the length of the third side.

From the other end of the base line, draw another

draw a pentagon. Refer to figure 14-20 as you read the

arc that intersects the first arc (view B).

following section.

4. Draw lines from the intersection point of these

1. Draw the diameter of the circle, shown as line

arcs to the ends of the base line. They are for

AOB (view A).

the sides of the triangle (view C).

2. Bisect radius OB of the circle (view B).

3. With D as a center and a radius equal to DC,

strike arc CE (view C).

4. With C as a center, strike arc FG passing through

An equilateral triangle has three equal sides. To

point E (view D).

draw this type of triangle, first draw one side as the base

line. Then, use the length of that side as the radius to

5. Distance CF or CG is equal to the length of one

draw intersecting arcs from each end of the base line

side of the pentagon. Mark off the other sides

(fig. 14-19, view A).

with the dividers (view E).

An isosceles triangle has two equal sides. To draw

an isosceles triangle, first draw the base. Then, draw

intersecting arcs from each end of the base line. Use

the length of one of the equal sides as the radius (fig.

14-19, view B).

A right triangle has a 90-degree angle. You can

draw a right triangle by using the method for bisecting

a line (refer to fig. 14-2). Draw a perpendicular from

the end of a line (refer to fig. 14-8), or draw a

14-13

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