Cube

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 458
Joined: Sun Aug 31, 2008 10:44 am
Thanked: 3 times
Followed by:1 members

Cube

by gmat009 » Thu Oct 09, 2008 6:29 am
For the cube shown above[see attached], what is the degree measure of PQR?

A. 30
B. 45
C. 60
D. 75
E. 90
Attachments
Cube.doc
(32.5 KiB) Downloaded 192 times
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 145
Joined: Mon Sep 29, 2008 1:14 am
Thanked: 13 times

by mental » Thu Oct 09, 2008 7:36 am
SIMILAR POST WAS DISCUSSED A DAY OR SO BACK

stop answered it well

all the three sides of triangle PQR are equal, as the are diagonals of the respective sides of cube

hence PQR is equilateral triangle
all angles = 60 (C)

Legendary Member
Posts: 833
Joined: Mon Aug 04, 2008 1:56 am
Thanked: 13 times

by vivek.kapoor83 » Thu Oct 09, 2008 8:21 am

Senior | Next Rank: 100 Posts
Posts: 31
Joined: Tue Dec 18, 2018 8:42 pm

by Krabhay » Tue Dec 18, 2018 9:17 pm
All the three sides of triangle PQR are face diagonals of a cube.
If the side of the cube is 'a', then PQ = QR = PR = a x sqrt(2)
So, the triangle PQR is an equilateral triangle. Hence, all the angles are of 60.