Definition and Properties of Pyramids
Definition and properties of pyramids is a Grade 7 geometry concept in Big Ideas Math Advanced 2, Chapter 14: Surface Area and Volume. A pyramid is a 3D solid with a polygonal base and triangular lateral faces that all meet at a single apex point. Pyramids are named by their base shape — a square pyramid has a square base, and the Great Pyramid of Giza is a real-world example.
Key Concepts
A pyramid is a 3D figure formed by connecting all points on a polygonal base to a single point not on the plane of the base, called the apex or vertex. The polygonal base can be any polygon (triangle, square, pentagon, etc.), and the triangular faces that connect the base to the apex are called lateral faces.
Common Questions
What is a pyramid in geometry?
A pyramid is a 3D solid formed by connecting all points on a polygonal base to a single apex point above the base. The sides are triangular faces called lateral faces.
How are pyramids named?
Pyramids are named by the shape of their base. A triangular pyramid has a triangular base, a square pyramid has a square base, and a pentagonal pyramid has a pentagonal base.
How is a pyramid different from a prism?
A pyramid has one polygonal base and triangular lateral faces that meet at an apex. A prism has two identical parallel polygon bases connected by rectangular lateral faces.
What textbook covers the definition of pyramids in Grade 7?
Big Ideas Math Advanced 2, Chapter 14: Surface Area and Volume covers the definition and properties of pyramids as 3D figures.