Faq/Draw/105

How do I draw a regular equilateral triangle?
The Drawing toolbar has a button to draw an isosceles triangle but not an equilateral triangle. To draw one, you must do a little geometry. In fact, an equilateral triangle is an isosceles triangle whose height h is:

$$h=\mathit{a.}\sin \left(\frac{\Pi }{3}\right)=\mathit{a.}\sin \left(60\circ \right)=\mathit{a.}\frac{\sqrt{3}}{2}\approx a\times \mathrm{0.866}$$ with a representing the length of any edge of the triangle.

To draw an equilateral triangle:


 * click on the triangle to the right of the Basic Shapes icon to open the Basic Shapes toolbar. In the toolbar, click on the Isosceles Triangle button.




 * click and drag to draw a triangle of about the size desired;
 * select the menu;
 * make sure Keep ratio is unchecked;
 * adjust:
 * the height so that it equals the width multiplied by 0.866,
 * the width so that it equals the height divided by 0.866,or
 * both, maintaining the proportion 0.866 between the height and the width;
 * If you change the size of the triangle, click Keep ratio to keep the length of the three sides equal.
 * Click OK.

Another way to create equilateral triangle is to:


 * Draw first edge:
 * Draw a line, holding, so it is a straight line.
 * Click on it, press to open properties.
 * Tab Position and Size, set Width to expected length.
 * Click OK.


 * Draw second edge:
 * Copy and paste, to create a copy.
 * Press to open properties.
 * Tab Rotation, select Pivot Point on a left position and set Rotation Angle to 60".
 * Draw third edge:
 * Create another copy of the base line with.
 * Press to open properties.
 * Tab Rotation, select Pivot Point on a right position and set Rotation Angle to 300".
 * Combine edges in one shape:
 * Select all lines.
 * Select menu entry or.