Step by step
The question
Question: how many lines of symmetry does a regular pentagon have?
1 Try the folds
Imagine folding the shape along a line.
If the two halves match exactly, it is a line of symmetry.
Fold through a corner and the middle of the opposite side.
The halves match: line 1.
Fold through a corner and the middle of the opposite side.
The halves match: line 2.
Fold through a corner and the middle of the opposite side.
The halves match: line 3.
Fold through a corner and the middle of the opposite side.
The halves match: line 4.
Fold through a corner and the middle of the opposite side.
The halves match: line 5.
2 Count the lines
We found 5.
So a regular pentagon has 5 lines of symmetry.
Careful!
Each fold goes through a corner and the middle of a side.
Count each fold once: 5, not 10.
3 Check
Let's check: a regular shape has as many lines of symmetry as sides.
5 sides, 5 lines.
Right!
Let's look back.
First: try the folds.
Then: count the lines.
Last: check.