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.
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.
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.
Make sure the arc passes at least halfway across the base.
For example, you might know that the isosceles triangle has two equal sides of 7 cm, or you might be given a line segment representing the side length. You also know that the angle between the sides is 50 degrees.
For example, you might need to draw a 50-degree angle. Since the sides of the triangle are 7 cm, the vectors should be a little longer than 7 cm long. You can use a ruler or your compass set to the appropriate length to measure.
For example, if you know that the side lengths are 7 cm, then use a ruler to open your compass 7 cm wide.
For example, you might know that an isosceles triangle has a base measuring 9 cm, with two adjacent 45-degree angles.
You can also draw the base by setting the compass to the same width as a provided line segment. Draw an endpoint. Make the other endpoint using the compass. Then use a straightedge to connect the two endpoints.
For example, you might have an isosceles triangle with a base of 5 cm and a height of 2. 5 cm.
If using a line segment instead of a measurement, draw the base by setting the compass to the width of the base. Draw an endpoint. Use the compass to draw the second endpoint. Then, connect the endpoints using a straightedge. [6] X Research source
You can also use a ruler and a protractor to bisect the line. Divide the length of the base in half. Use the ruler to draw a midpoint. Then, use a protractor to draw a line at this midpoint that intersects the base at a 90-degree angle.
