Free Understanding symmetry Grade 1 2D Shapes Worksheets - Free Printable

Let's solve this step-by-step based on the worksheet titled "Lines of Symmetry".

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🔷 Understanding the Task

We are asked to determine whether the dotted line drawn on each shape is a line of symmetry. A line of symmetry divides a shape into two parts that are mirror images of each other — meaning both sides are exactly the same when folded along the line.

We need to:
- Examine each shape.
- Check if the dotted line splits it into two identical halves.
- Circle the shape only if the dotted line is a line of symmetry.

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🔍 Let’s Analyze Each Shape:

#### 1. Orange Parallelogram (Top Left)
- The dotted line goes from one corner to the opposite corner (a diagonal).
- In a general parallelogram, diagonals do not create symmetrical halves unless it's a special type (like a rhombus or rectangle).
- This is a slanted parallelogram, so the two sides are not mirror images.
✔ Not a line of symmetry.

#### 2. Blue Rectangle (Middle Top)
- Dotted line runs diagonally from top-left to bottom-right.
- A rectangle has two lines of symmetry: vertical and horizontal midlines, but not diagonals (unless it's a square).
- Diagonals do not produce mirror-image halves in a non-square rectangle.
✔ Not a line of symmetry.

#### 3. Purple Star (Top Right)
- The dotted line goes vertically through the center.
- A regular 5-pointed star has 5 lines of symmetry, each going through a point and the midpoint of the opposite side.
- This line passes through a point and the middle of the opposite side → yes, it divides the star into two matching halves.
✔ Yes, it is a line of symmetry. → Circle this shape.

#### 4. Green Heart (Middle Left)
- The dotted line is horizontal, cutting across the middle.
- A heart is symmetric vertically, not horizontally.
- The top and bottom are not mirror images (the top is pointed, bottom is curved).
✔ Not a line of symmetry.

#### 5. Blue Triangle (Middle Right)
- The triangle looks like an equilateral triangle, and the dotted line goes from one vertex to the midpoint of the opposite side.
- In an equilateral triangle, all three medians are also lines of symmetry.
- This line divides the triangle into two congruent right triangles.
✔ Yes, it is a line of symmetry. → Circle this shape.

#### 6. Yellow Square (Center)
- Dotted line is a diagonal from top-left to bottom-right.
- A square has four lines of symmetry: two diagonals and two midlines.
- Diagonals are lines of symmetry in a square.
✔ Yes, it is a line of symmetry. → Circle this shape.

#### 7. Pink Pentagon (Bottom Left)
- It's a regular pentagon, and the dotted line goes from one vertex to the midpoint of the opposite side.
- A regular pentagon has five lines of symmetry, each passing through a vertex and the midpoint of the opposite side.
- So this dotted line is a line of symmetry.
✔ Yes, it is a line of symmetry. → Circle this shape.

#### 8. Red Diamond (Bottom Right)
- This is a square rotated 45°, so it looks like a diamond.
- The dotted line is vertical, running through the center.
- Since it's a square, any line through the center (vertical, horizontal, or diagonal) is a line of symmetry.
- Vertical line through center → yes, it divides it into two identical halves.
✔ Yes, it is a line of symmetry. → Circle this shape.

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✔ Final Answer: Circle the following shapes:

- Purple Star
- Blue Triangle
- Yellow Square
- Pink Pentagon
- Red Diamond

> ✘ Do not circle:
> - Orange Parallelogram
> - Blue Rectangle
> - Green Heart

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📝 Summary:

Shapes with the dotted line as a line of symmetry (to be circled):
1. Purple Star
2. Blue Triangle
3. Yellow Square
4. Pink Pentagon
5. Red Diamond

These are the ones where folding along the dotted line would make both sides match perfectly.

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✔ Answer: Circle the star, triangle, square, pentagon, and red diamond.