A(1,4)A(1,4) and B(6,7)B(6,7) and C(4,2)C(4,2) are the vertices of the triangle.
Compute for the length of the sides first.
Distance AB
d_(AB)=sqrt((x_A-x_B)^2+(y_A-y_B)^2)dAB=√(xA−xB)2+(yA−yB)2
d_(AB)=sqrt((1-6)^2+(4-7)^2)dAB=√(1−6)2+(4−7)2
d_(AB)=sqrt((-5)^2+(-3)^2)dAB=√(−5)2+(−3)2
d_(AB)=sqrt(25+9)dAB=√25+9
d_(AB)=sqrt(34)dAB=√34
Distance BC
d_(BC)=sqrt((x_B-x_C)^2+(y_B-y_C)^2)dBC=√(xB−xC)2+(yB−yC)2
d_(BC)=sqrt((6-4)^2+(7-2)^2)dBC=√(6−4)2+(7−2)2
d_(BC)=sqrt((2)^2+(5)^2)dBC=√(2)2+(5)2
d_(BC)=sqrt(4+25)dBC=√4+25
d_(BC)=sqrt(29)dBC=√29
Distance BC
d_(AC)=sqrt((x_A-x_C)^2+(y_A-y_C)^2)dAC=√(xA−xC)2+(yA−yC)2
d_(AC)=sqrt((1-4)^2+(4-2)^2)dAC=√(1−4)2+(4−2)2
d_(AC)=sqrt((-3)^2+(2)^2)dAC=√(−3)2+(2)2
d_(AC)=sqrt(9+4)dAC=√9+4
d_(AC)=sqrt(13)dAC=√13
Perimeter =sqrt(34)+sqrt(29)+sqrt(13)=3.60555=√34+√29+√13=3.60555
God bless....I hope the explanation is useful.