Are all the surfaces flat? What does this tell us about whether or not it is a polyhedron? How many bases does the figure have?
Solid
Base
Faces
Edges
Vertices
Triangular Pyramid
ADC
ADC, ABD, BDC, ACB
AB, AD, BD, DC, BC, AC
A, B, C, D
Practice makes perfect
Let's begin by reviewing the definition of a polyhedron.
A polyhedron is a solid composed of all flat surfaces that enclose a single region of space.
Examining the given solid, we can see that it meets this definition.
Therefore, it is a polyhedron.
Now, let's consider two types of polyhedrons.
A prism has two parallel congruent bases connected by parallelogram faces.
A pyramid has one polygonal base and three or more triangular faces that meet at a common vertex.
The solid has one base that is a triangle and three triangular faces that meet at the common vertex, so it is a triangular pyramid.
Let's recall the meaning of the features that we want to identify.
