The measure of sides of triangle with given points are
QR = 3 (square root of 5) unit
RT = 9 (square root of 2) unit
TQ = (square root of 13) unit
The coordinate of Triangle QRT as :
Q = ( - 2 , - 1 )
R = ( 1 , 5 )
T = ( - 8 , - 4 )
Now , The Distance between the points can be measure as :
QR = {square root of (x^2 - x^1)^2+(y^2-y^1)^2}
Or, QR = (square root of 45) = 3(square root of 5) unit
Likewise,
RT = {square root of (x^2 - x^1)^2+(y^2-y^1)^2}
Or, RT = (square root of 162) = 9 (square root of 2) unit
And
TQ = {square root of (x^2 - x^1)^2+(y^2-y^1)^2}
Or, TQ = (square root of 13) unit
Thus, the measure of sides of triangle with given points are
QR = 3 (square root of 5) unit
RT = 9 (square root of 2) unit
TQ = (square root of 13) unit
I hope this helps! o(〃＾▽＾〃)o