MathDB
Pyramid Problem

Source: 1994 National High School Mathematics League, Exam One, Problem 5

March 1, 2020
geometry3D geometrypyramid

Problem Statement

In regular nn-regular pyramid, the range value of dihedral angle of two adjacent sides is (A)(n2nπ,π)(B)(n1nπ,π)(C)(0,π2)(D)(n2nπ,n1nπ)\text{(A)}\left(\frac{n-2}{n}\pi,\pi\right)\qquad\text{(B)}\left(\frac{n-1}{n}\pi,\pi\right)\qquad\text{(C)}\left(0,\frac{\pi}{2}\right)\qquad\text{(D)}\left(\frac{n-2}{n}\pi,\frac{n-1}{n}\pi\right)