First slide

Straight lines in 3D

Question

The foot of the perpendicular from (a,b,c) on the line $x = y = z$ is the point $(r, r, r)$ where

Moderate

A

$r = a + b + c$
B

$r = 3 (a + b + c)$
C

$3 r = a + b + c$
D

$r = 4 (a + b + c)$

Solution

Dr s of line is 1,1,1
dr s of line joining (a,b,c)&(r,r,r) isr-a,r-b,r-c
both are perpendicular
1(r-a)+1(r-b)+1(r-c)=0

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App