Identify if the dotted line in each figure is a line of symmetry.
A worksheet titled "Line of Symmetry" with nine figures, each containing a dotted line to determine if it is a line of symmetry, with spaces to write 'Yes' or 'No'.
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Step-by-step solution for: Line of symmetry online exercise
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Show Answer Key & Explanations
Step-by-step solution for: Line of symmetry online exercise
Let's analyze each figure to determine whether the dotted line shown is a line of symmetry. A line of symmetry divides a shape into two parts that are mirror images of each other.
We’ll go through each figure one by one:
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1. Pentagon (regular)
- The dotted line goes vertically through the top vertex and the center.
- A regular pentagon has 5 lines of symmetry, one from each vertex to the midpoint of the opposite side.
- This line passes through the top vertex and splits the shape symmetrically.
✔ Yes
2. Crescent-shaped figure (like a Pac-Man with a bite taken out)
- The dotted line is horizontal, going through the middle.
- If you fold along this line, the top and bottom won't match because the "bite" is on one side only.
✘ No
3. Number 9
- The dotted line is diagonal from top-left to bottom-right.
- The number 9 is not symmetrical along this diagonal — the top part is curved, the bottom is open.
✘ No
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4. Oval (ellipse)
- Dotted line is horizontal, across the center.
- An oval has two lines of symmetry: vertical and horizontal.
- This horizontal line divides it into top and bottom halves that are mirror images.
✔ Yes
5. Letter W in red box
- Dotted line is vertical, down the center.
- The letter W has a vertical line of symmetry — left and right sides are mirror images.
✔ Yes
6. Fork
- Dotted line is horizontal, across the middle.
- The fork has tines at the top and a handle below. The top and bottom are not symmetric.
- Folding horizontally would not make the two halves match.
✘ No
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7. Letter A
- Dotted line is vertical, down the center.
- The letter A has a vertical line of symmetry — left and right are mirror images.
✔ Yes
8. Zero (0)
- Dotted line is diagonal (from bottom-left to top-right).
- A circle or zero has infinite lines of symmetry, but this diagonal line does not divide it into mirror-image halves?
Wait — actually, a perfect circle (or zero) is symmetric along any line through its center.
But here, the dotted line goes through the center, so even diagonally, it should reflect.
However, look closely: the zero is drawn as an ellipse? Or slightly stretched?
But assuming it’s a standard circular zero, any line through the center is a line of symmetry.
So yes, even a diagonal line through the center works.
✔ Yes
> Note: Even if it's slightly elliptical, unless specified otherwise, we assume it's symmetric. The dotted line passes through the center, so it reflects both sides.
✔ Yes
9. Square
- Dotted line is horizontal, through the center.
- A square has 4 lines of symmetry: 2 diagonals, 1 vertical, 1 horizontal.
- This horizontal line divides it into top and bottom halves — equal and mirror images.
✔ Yes
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10. Triangle (equilateral)
- Dotted line is vertical, from top vertex to base center.
- An equilateral triangle has 3 lines of symmetry — one from each vertex to the midpoint of the opposite side.
- This line divides it into two congruent right triangles.
✔ Yes
11. Human figure (stick figure)
- Dotted line is horizontal, across the waist.
- The head is above, legs below — they’re not mirror images.
- Top half (head) vs. bottom half (legs) are not symmetric.
✘ No
12. Pot with lid
- Dotted line is vertical, through the center.
- The pot is symmetrical — both sides have handles, and the shape is balanced.
- Left and right are mirror images.
✔ Yes
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| Figure | Answer |
|--------|--------|
| 1. Pentagon | Yes |
| 2. Crescent | No |
| 3. Number 9 | No |
| 4. Oval | Yes |
| 5. W | Yes |
| 6. Fork | No |
| 7. A | Yes |
| 8. Zero | Yes |
| 9. Square | Yes |
| 10. Triangle | Yes |
| 11. Human | No |
| 12. Pot | Yes |
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- Yes: 1, 4, 5, 7, 8, 9, 10, 12 → 8 figures
- No: 2, 3, 6, 11 → 4 figures
> You can now fill in the boxes accordingly.
We’ll go through each figure one by one:
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Row 1
1. Pentagon (regular)
- The dotted line goes vertically through the top vertex and the center.
- A regular pentagon has 5 lines of symmetry, one from each vertex to the midpoint of the opposite side.
- This line passes through the top vertex and splits the shape symmetrically.
✔ Yes
2. Crescent-shaped figure (like a Pac-Man with a bite taken out)
- The dotted line is horizontal, going through the middle.
- If you fold along this line, the top and bottom won't match because the "bite" is on one side only.
✘ No
3. Number 9
- The dotted line is diagonal from top-left to bottom-right.
- The number 9 is not symmetrical along this diagonal — the top part is curved, the bottom is open.
✘ No
---
Row 2
4. Oval (ellipse)
- Dotted line is horizontal, across the center.
- An oval has two lines of symmetry: vertical and horizontal.
- This horizontal line divides it into top and bottom halves that are mirror images.
✔ Yes
5. Letter W in red box
- Dotted line is vertical, down the center.
- The letter W has a vertical line of symmetry — left and right sides are mirror images.
✔ Yes
6. Fork
- Dotted line is horizontal, across the middle.
- The fork has tines at the top and a handle below. The top and bottom are not symmetric.
- Folding horizontally would not make the two halves match.
✘ No
---
Row 3
7. Letter A
- Dotted line is vertical, down the center.
- The letter A has a vertical line of symmetry — left and right are mirror images.
✔ Yes
8. Zero (0)
- Dotted line is diagonal (from bottom-left to top-right).
- A circle or zero has infinite lines of symmetry, but this diagonal line does not divide it into mirror-image halves?
Wait — actually, a perfect circle (or zero) is symmetric along any line through its center.
But here, the dotted line goes through the center, so even diagonally, it should reflect.
However, look closely: the zero is drawn as an ellipse? Or slightly stretched?
But assuming it’s a standard circular zero, any line through the center is a line of symmetry.
So yes, even a diagonal line through the center works.
✔ Yes
> Note: Even if it's slightly elliptical, unless specified otherwise, we assume it's symmetric. The dotted line passes through the center, so it reflects both sides.
✔ Yes
9. Square
- Dotted line is horizontal, through the center.
- A square has 4 lines of symmetry: 2 diagonals, 1 vertical, 1 horizontal.
- This horizontal line divides it into top and bottom halves — equal and mirror images.
✔ Yes
---
Row 4
10. Triangle (equilateral)
- Dotted line is vertical, from top vertex to base center.
- An equilateral triangle has 3 lines of symmetry — one from each vertex to the midpoint of the opposite side.
- This line divides it into two congruent right triangles.
✔ Yes
11. Human figure (stick figure)
- Dotted line is horizontal, across the waist.
- The head is above, legs below — they’re not mirror images.
- Top half (head) vs. bottom half (legs) are not symmetric.
✘ No
12. Pot with lid
- Dotted line is vertical, through the center.
- The pot is symmetrical — both sides have handles, and the shape is balanced.
- Left and right are mirror images.
✔ Yes
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✔ Final Answers (in order):
| Figure | Answer |
|--------|--------|
| 1. Pentagon | Yes |
| 2. Crescent | No |
| 3. Number 9 | No |
| 4. Oval | Yes |
| 5. W | Yes |
| 6. Fork | No |
| 7. A | Yes |
| 8. Zero | Yes |
| 9. Square | Yes |
| 10. Triangle | Yes |
| 11. Human | No |
| 12. Pot | Yes |
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✔ Summary:
- Yes: 1, 4, 5, 7, 8, 9, 10, 12 → 8 figures
- No: 2, 3, 6, 11 → 4 figures
> You can now fill in the boxes accordingly.
Parent Tip: Review the logic above to help your child master the concept of lines of symmetry worksheet.