12
A triangularbased pyramid (tetrahedron) has 4 faces, 6 edges and 4 vertices
8
depends on the dimensions of the 4 sides
Fact: a polygonal pyramid has a polygon for a base. Fact: A polygon with n sides (straws) has n vertices (balls of clay). Fact: A pyramid has one vertex (clay) at the top. Fact: Each vertex of the base has a side (straw) that connects it to the top vertex (clay). Question: How many sides does a hexagon have? (base straws) Question: How many vertices does a hexagon have? (base clay) Question: How many vertices are there all together, including the top one? (clay) Question: How many sides connect the base to the top vertex? (side straws) Question: How many sides (straws) are there all together? (straws)
8 straws.
12
6 straws are needed
8
8
10
16 straws.
A triangularbased pyramid (tetrahedron) has 4 faces, 6 edges and 4 vertices
8
8 straws 4 for the square base 4 for 1 each of the sides, to meet at the top.
depends on the dimensions of the 4 sides
6