Step-by-step explanation (beginner-friendly)
Goal: We need capital letters that have a horizontal line of symmetry only.
What does that mean?
- Horizontal symmetry ⟶ If you place a mirror across the middle horizontally (left–right line), the top part and bottom part look the same.
- Vertical symmetry ⟶ If you place a mirror through the middle vertically (up–down line), the left and right parts look the same.
- We are looking for letters that have horizontal symmetry but do not have vertical symmetry.
Check each matching letter
-
B
- Top curve and bottom curve are the same shape and size.
- Across a horizontal line through the middle, the letter looks unchanged ⇒ has horizontal symmetry.
- Left and right sides are not the same ⇒ no vertical symmetry.
-
C
- Top arc and bottom arc match across a horizontal middle line ⇒ has horizontal symmetry.
- A vertical mirror makes it face the other way ⇒ no vertical symmetry.
-
D
- Top half and bottom half (flat spine with a rounded side) match horizontally ⇒ has horizontal symmetry.
- Left and right are different ⇒ no vertical symmetry.
-
E
- Top and bottom arms are equal; the middle arm stays in the middle ⇒ has horizontal symmetry.
- Left and right are not the same ⇒ no vertical symmetry.
-
K
- The upper slanting arm and the lower slanting arm are arranged to mirror each other across a horizontal middle line ⇒ has horizontal symmetry.
- Left and right are different ⇒ no vertical symmetry.
Important note
We use the standard block form of capital letters. Some fonts may look slightly different, but in block letters the above checks hold.
Conclusion
The letters with only horizontal line of symmetry are: B, C, D, E, K.
Therefore, the number of such letters is: 5.