Step by step
The question
Question: how many lines of symmetry does a scalene triangle 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 straight down the middle.
The corners do not meet.
It is not a line of symmetry.
Fold through a corner and the middle of the opposite side.
The corners do not meet.
It is not a line of symmetry.
2 Count the lines
No fold works.
So a scalene triangle has 0 lines of symmetry.
lines of symmetry = 0
Careful!
All three sides are different.
No fold makes the halves match.
Careful: not 1 ✗
Let's look back.
First: try the folds.
Last: count the lines.
Answer
lines of symmetry = 0