3rd Grade Count Edges of 3D Shapes Worksheet: Faces and Vertices Too

How many corners does a box have? This 3rd grade count edges of 3D shapes worksheet turns that question into a careful counting game. Eight solids are drawn on a grid. Dashed lines show the hidden back of each shape. For every drawing, your child writes the number of faces, edges and vertices on three short lines. The set mixes prisms and pyramids with round shapes, like a cylinder and a cone. Page two is the answer key, with all 24 numbers filled in.

The answers, counted again on the drawings

We counted every solid again on the drawings of page one. The square pyramid has 8 edges, 5 faces and 5 vertices, and the triangular pyramid has 6, 4 and 4. The hexagonal prism has 18 edges, 8 faces and 12 vertices, while the box shape has 12, 6 and 8.

We fixed the original key before we shared it. It gave the hexagonal prism the numbers of the triangular pyramid, and it gave the cone two edges instead of one. This sheet counts a curved surface as a face and a curved rim as an edge. So the cylinder has 2 edges, 3 faces and 0 vertices. However, some books count only flat faces and straight edges, so check which rule your child's teacher uses.

At the table: count without missing a line

Edges are easy to count twice, so give your child a simple method. Your child puts a small tick on each edge as it is counted, including the dashed ones at the back. Then your child circles each vertex, where the edges meet in a point.

Prisms also follow a pattern that makes a good check. Count the sides of the base, and then the prism has three times as many edges, twice as many vertices and two more faces. For the hexagonal prism, 6 sides give 18 edges, 12 vertices and 8 faces. Faces, edges and vertices of 3D shapes are a review from grade 2. As a result, this page builds careful counting more than new ideas.

After the page: build the shapes at home

Hands-on models make the numbers easy to see. With straws for edges and small balls of modeling clay for vertices, your child can build a cube or a square pyramid. Afterwards, your child counts the straws and clay balls and compares them with the sheet. A cereal box works too, because your child can put a sticky note on each face. Finally, look for prisms and pyramids around the house, such as a tent, a roof or a can.