Fold the net. Find every face.

SparkClass

Unfold a solid, match each face, then add their areas.

CCSS 6.G.A.4
Live Folding Model
Solid · closed
3D · Same Fold State drag the fold slider A three-dimensional solid that unfolds by hinged faces A closed rectangular prism at 0 percent unfolded.
2D · Flat Net Map click to match The flat net with matching face colors A valid rectangular prism net with six labeled faces.
01

Closed solid. Every face is ready to unfold.

Front · 5 × 2 = 10 u²
Your Face Sum626 of 6 faces
→
Full Surface Area62square units
·
Dimensions5 × 3 × 2units

Teacher notes · Fold the Net

The two views keep face colors and names matched. The 3D faces rotate around shared edges; they do not fade into a separate net picture.

1

Predict before unfolding

At 0%, ask: Which faces are opposite? Which edges will meet? Drag slowly to 100% and revise predictions.

2

Build the sum one face at a time

Clear the face list, click a face in either view, then include it in the sum. Insist on a dimension-based area term before adding.

3

Challenge the meaning of a valid net

Select “Invalid challenge · two lids.” At 0%, Top and Bottom coincide and the opposite opening is uncovered. Equal total area does not prove that a net can close.

4

Separate slant height from 3D height

For the square pyramid, each triangular face has area ½as, where s is measured along the triangle. The perpendicular 3D height H satisfies H² + (a/2)² = s².

CCSS 6.G.A.4: Represent three-dimensional figures using nets made up of rectangles and triangles, and use the nets to find the surface area of these figures. Apply these techniques in the context of solving real-world and mathematical problems.