Congruence in mathematics means being equal in shape and size, and it is used to describe angles, shapes and line segments. The congruent symbol is an equals sign with a tilde over the top of it, ≅, and once you can define congruence, it's easy to use the symbol correctly in principle. However, in practice, the main issue you encounter is producing the symbol in word processing programs or online. Fortunately, you can use several different methods to produce the congruent sign in word processing programs and in other environments such as LaTex or KaTex, and they're easy to learn.
Copying and Pasting
The easiest way to use the congruent symbol is to copy it from another source that uses the symbol and paste it where you need it. Highlight the symbol, ≅, press CTRL and C at the same time to copy it, and then go to where you want to use the symbol and press CTRL and V at the same time to paste it. This method is low effort, and it works in almost any program or environment, but other methods are more efficient when you don't have a pre-existing example of a congruent symbol.
Microsoft Word or Google Docs
Microsoft Word is one of the most common word processing programs in the world. Word versions have a built-in Symbols feature that makes it easy to type the congruent symbol. Select the Insert tab and click the drop-down arrow underneath Symbol. Click More Symbols to bring up the Symbol dialogue box.
Use the drop-down menu beside Subset and choose Mathematical Operators. Scan the grid of symbols for the congruent symbol and highlight it with a left-click of your mouse. Click Insert to place it into your document at the cursor position. You can always copy or cut the symbol and move it to another location if your cursor isn't in the right location when you bring up the window.
The process is even more straightforward in Office 365 Word. Select Insert in the ribbon and choose Equation. Select the congruent symbol from the symbol grid on the ribbon to paste it into the document.
For Google Docs, click Insert at the top of the screen and choose Special characters from the drop-down menu. Type approximately equal to in the search field of the window that appears. Click on the congruent symbol in the search results to paste it into the document. It's worth noting that for both Google Docs and Microsoft Word, the symbol is called "approximately equal to."
Congruent Sign Alt Code
Alt codes are another method you can use to produce symbols on most word processing programs and email programs. You can use these as long as you have a keyboard with a number pad section, and you need to make sure that Num Lock is on before attempting this method. Turn it on by pressing the Num Lock key so that the light activates.
Produce the congruent symbol by holding down the Alt key while typing in the code 8773. While remembering the specific code might not be an ideal solution, it is often much easier to use the alt code method than to navigate to the symbol using the method in the previous section. It also works across multiple platforms, which is useful if you're likely to need to type it in more than one program.
In LaTex or KaTex
The LaTex language is excellent for displaying math, so there is a simple way to type the congruent symbol in LaTex and KaTex. Type \cong into the LaTex or KaTex field to render the congruent sign. You can also create the sign for not congruent using \ncong in LaTex or KaTex.