How to Construct an Isosceles Triangle

Step-by-Step Guide

1. 1

   Step 1: Assess what you know.

   To use this method, you should know the length of the triangle’s base and the length of the two equal sides.
   
   You can also use this method if you are given line segments representing the base and sides instead of the measurements.
   
   For example, you might know that the base of a triangle is 8 cm, and its two equal sides are 6 cm, or you might be given two lines, one representing the base, and one representing the two sides.
2. 2

   Step 2: Draw the base.

   Use a ruler to make sure that your line is measured exactly.
   
   For example, if you know that the base is 8 cm long, use a sharp pencil and a ruler to draw a line exactly 8 cm long.
   
   If using a given line segment instead of a measurement, draw the base by setting the compass to the width of the provided base.
   
   Make an endpoint, then use the compass to draw the other endpoint.
   
   Connect the endpoints using a straightedge., To do this, open the compass to the width of the equal side lengths.
   
   If you are given the measurement, use a ruler.
   
   If you are given a line segment, set the compass so that it spans the length of the line.
   
   For example, if the side lengths are 6 cm, open the compass to this length.
   
   Or, if provided a line segment, set the compass to the segment's length. , To do this, place the tip of the compass on one of the base’s endpoints.
   
   Sweep the compass in the space above the base, drawing an arc.
   
   Make sure the arc passes at least halfway across the base. , Without changing the width of the compass, place the tip on the other endpoint of the base.
   
   Draw an arc that intersects the first one. , Use a ruler to draw lines connecting the point where the arcs intersect to either endpoint of the base.
   
   The resulting figure is an isosceles triangle.
3. 3

   Step 3: Set the compass.

4. 4

   Step 4: Draw an arc above the base.

5. 5

   Step 5: Draw an intersecting arc above the base.

6. 6

   Step 6: Draw the sides of the triangle.

Detailed Guide

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