MathDB

Consider the regular pyramid

VABCD

with the vertex in

V

which measures the angle formed by two opposite lateral edges is

45^o

. The points

M,N,P

are respectively, the projections of the point

A

on the line

VC

, the symmetric of the point

M

with respect to the plane

(VBD)

and the symmetric of the point

N

with respect to

O

. (

O

is the center of the base of the pyramid.)
a) Show that the polyhedron

MDNBP

is a regular pyramid.
b) Determine the measure of the angle between the line

ND

and the plane

(ABC)

Problem Statement