Grade 4 Geometry worksheet on reflections, featuring six pairs of shapes with dashed lines to identify mirror images.

Problem Description:

The task is to identify which images show reflections (flips) across a given line of symmetry. A reflection occurs when one side of the image is a mirror image of the other side with respect to a line of symmetry.

Solution Approach:

1. Understand Reflections:
- A reflection means that if you were to fold the paper along the dashed line, the two sides would match perfectly.
- The shapes on either side of the line should be identical in size, shape, and orientation but mirrored.

2. Analyze Each Pair:
- For each pair of shapes, check if the right side is a mirror image of the left side with respect to the dashed line.

3. Check for Symmetry:
- Ensure that corresponding points on both sides are equidistant from the line of symmetry.

Analysis of Each Row:

#### Row 1: Lightning Bolt
- The lightning bolt on the left is not a mirror image of the lightning bolt on the right.
- The shapes are different, so this is not a reflection.

#### Row 2: Parallelograms
- The parallelogram on the left is a mirror image of the parallelogram on the right with respect to the dashed line.
- Both shapes are identical in size, shape, and orientation when reflected.
- This is a reflection.

#### Row 3: Hearts
- The heart on the left is not a mirror image of the heart on the right.
- The hearts are rotated differently, so this is not a reflection.

#### Row 4: Crescent Shapes
- The crescent shape on the left is a mirror image of the crescent shape on the right with respect to the dashed line.
- Both shapes are identical in size, shape, and orientation when reflected.
- This is a reflection.

#### Row 5: Arrows
- The arrow on the left is not a mirror image of the arrow on the right.
- The arrows point in different directions, so this is not a reflection.

#### Row 6: Trapezoids
- The trapezoid on the left is a mirror image of the trapezoid on the right with respect to the dashed line.
- Both shapes are identical in size, shape, and orientation when reflected.
- This is a reflection.

#### Row 7: Diamonds
- The diamond on the left is a mirror image of the diamond on the right with respect to the dashed line.
- Both shapes are identical in size, shape, and orientation when reflected.
- This is a reflection.

#### Row 8: Squares
- The square on the left is not a mirror image of the square on the right.
- The squares have different internal patterns, so this is not a reflection.

Final Answer:

The pairs that show reflections are:
- Row 2: Parallelograms
- Row 4: Crescent Shapes
- Row 6: Trapezoids
- Row 7: Diamonds

Thus, the boxes to check are:
- Row 2
- Row 4
- Row 6
- Row 7

$$
\boxed{2, 4, 6, 7}
$$