MathDB

angles between plane, distance, cube (2014 Romanian NMO grade VIII P2)

Source:

May 28, 2020

geometry3D geometrycubeangledistance

Problem Statement

Let

ABCDA'B'C'D'

be a cube with side

AB = a

. Consider points

E \in (AB)

and

F \in (BC)

such that

AE + CF = EF

.
a) Determine the measure the angle formed by the planes

(D'DE)

and

(D'DF)

.
b) Calculate the distance from

D'

to the line

EF