# Math Help - triangle vertices

1. ## triangle vertices

FInd the area of the triangle whose verices are P(1, 1, -1), Q(1, -1, 1) and R(-1, 1, 1)

really need some help find the area for this problem please.

2. Hello, rcmango!

FInd the area of the triangle whose verices are: P(1,1,-1), Q(1,-1,1), R(-1,1,1)

The "symmetry" of the coordinates made me suspicious. . ._
I found the lengths of the sides to be: PQ = QR = RP = 2√2
. . It's an equilateral triangle!

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _
The area of an equilateral triangle of side x is: .A .= .(√3/4)x²

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Therefore: .Area .= .(√3/4)(2√2)² .= .2√3