The feature of rotational symmetry in capital letters describes how the letter looks the same after being rotated. Z, S, H, N, and O are capital letters with rotational symmetry. A, H, I, M, O, T, U, V, W, X, and Y are some letters with a vertical line of symmetry. Letters with horizontal or diagonals lines of symmetry are also included.
In mathematics, physics, and chemistry, rotationally symmetric objects exhibit the same shape regardless of their orientation. Thus, all axes of symmetry are great circles (lines through the center of a sphere that are perpendicular to any point on the surface). For example, the axis of a ringed planet like Jupiter is the circle that passes through its north and south poles. The term "rotationally symmetric" can be applied to two-dimensional figures such as triangles, squares, and pentagons, as well as to three-dimensional shapes such as spheres, cubes, and pyramids. In these cases, the phrase "with rotational symmetry" means that if you were to rotate the figure counterclockwise around an axis touching one of its corners, then it would still look the same when viewed from any other angle.
All capitals but M have some form of rotational symmetry.
The uppercase letters H, I, O, and X all have symmetrical horizontal and vertical lines. These letters can be used to balance other letters that don't have such lines as a compensating feature, for example, the lowercase i and o.
Other capitals with horizontal and vertical lines include A, C, D, E, G, J, K, M, N, P, R, S, T, V, and W. The only letter that doesn't have symmetrical lines is Z. It is known as an "irregular" letter because it lacks the regular horizontal and vertical lines of most other letters.
See how many you can identify in the picture below. You may see some letters twice because they're mirrored image pairs. For example, the pair of h's look like they could be part of one letter but they're actually separate letters because they have different values. There are 26 letters in the English alphabet.
Letters with horizontal lines of symmetry, such as B and D, have top and bottom sections that match. Some letters, such as X, H, and O, have both vertical and horizontal symmetry lines. Some, like P, R, and N, have no symmetry lines. The parts that match together for each letter are shown in different colors to make them visible.
Older versions of the Unicode standard included a second version of O called "ordinal indicator". This character was used to indicate numbers in alphabetical order, similar to the use of the number sign (#) today. It looked like this: Ⓐ.
This character is now deprecated in favor of the decimal-encoded o glyph, which can be found at U+002o (10). This change was made in Unicode 9.0. Before then, ordinal indicators were encoded as part of other characters, most often combining marks (?). Here are some examples from Unicode 7.0: ⓐ, ①, and ➡.
The decimal-encoding of O⇒o has been available since Unicode 5.1. Before then, it was encoded as part of other characters, usually combining marks: ⅛, ⅜, and ⅞.
Combining marks are characters that modify another character's appearance or function while still allowing it to be interpreted correctly.
Vertically symmetrical capital letters include A, M, T, U, V, W, and Y; horizontally symmetrical capital letters include B, C, D, E, and K; both horizontally and vertically symmetrical capital letters include H, I, and X; and infinitely symmetrical capital letters include O. None of these letters are truly symmetrical; however, some writers may choose to write them that way for aesthetic purposes.
The only truely symmetrical letter is the diadem (or crown) signifying royalty or dignity. Other than this, all other letters are not symmetrical.
As you can see, the letter D is not symmetrical at all. It has a lower-case d below it showing that it's not symmetrical vertically.
In fact, there are several words in the dictionary that show the asymmetry of the letter D: diverse, dissolve, distort, entangle, enmesh, ensnare, and disentangle.
So, yes, the letter D is an asymmetric letter.
Which letters are asymmetrical? F, G, J, L, N, P, Q, R, S, and Z are the only letters in the English alphabet that lack a line of symmetry. That is, there is no letter which exactly reverses its shape when viewed from above or below.
Why aren't other letters considered symmetrical? Because most other letters have parts that look like dashes or dots. There are three types of characters in the English alphabet: consonants, vowels, and symbols (.). Consonants are words' main sound units. They are usually divided into two groups: plosives and fricatives. Plosives make a loud noise when hit or bitten, while fricatives make a low noise. Examples of consonants are B, D, G, V, and W. Symbols are used to mark the beginning or end of sentences or words. Examples include the exclamation point! and the question mark?
Vowels are the smallest unit of speech; they are the sounds that make up words such as my, her, our, its, your, their, there's, and our. There are five vowels in English: A, E, I, O, U. Some languages, such as Latin, have more than five vowels because they use more than one vowel sound for some words.
The letter M is no exception. The symbol for marriage, ·, has line symmetry but does not represent any real object.
There are 14 letters with line symmetry: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z. They are shown in red in the diagram below.
Symmetry is a very important concept in geometry because it tells us how objects are related to one another. Lines can be drawn through any letter that has line symmetry. For example, there is exactly one line through the middle of the M. This line divides the upper part of the letter from the lower part. Any property held by one part of the letter is also held by the other part. For example, if you measure a thing's length, you will get the same number whether you measure it from top to bottom or from bottom to top. There are two types of symmetry: spatial and mirror. Spatial symmetry occurs when something is interchangeable with its mirror image. So, the front and back of an object, the right and left sides, are identical.
The letter Z exemplifies "2-fold Rotational Symmetry," since it retains its appearance after being spun 180 degrees around its center. However, it lacks mirror symmetry. This type of shape is known as "chiral," which implies it cannot be placed on its mirror counterpart. A circular object that can't be mirrored completely is called a "chiral" object.
Although the letter Z is not symmetrical, it still has some interesting properties. For example, it is the only regular polygon with an even number of sides other than squares and rectangles. It's also the only polygon with 10 or more sides that isn't a rectangle or square.
Furthermore, no two copies of the same polyhedron are identical, because they contain different numbers of faces in different arrangements. Thus, there are many possible shapes for one molecule of zinc sulfate heptahydrate.
However, despite this variety, all zircons share several similar properties. They always have 8 face planes and 12 edge planes, and their surface patterns usually consist of 6-petal flowers with triangular centers. These properties make zircon very useful for creating tools that cut easily but don't break off parts of the rock when removed.
In addition to being a chemical compound, zinc sulfate heptahydrate is also used as a food additive for its preservative qualities.