Equation for finding distance between #2# coordinates #=# #sqrt((x_2-x_1)^2+(y_2-y_1)^2)#
Let,
#(7,6)=#point #A#
#(4,5)=#point #B#
#(3,1)=#point #C#
Distance between #AB#
#x_1=7,x_2=4,y_1=6,y_2=5#
#AB=sqrt((4-7)^2+(5-6)^2)#
#=>sqrt((-3)^2+(-1)^2#
#=>sqrt(9+1)#
#=>sqrt10#
#AB=sqrt10#
Distance between #BC#
#x_1=4,x_2=3,y_1=5,y_2=1#
#BC=sqrt((3-4)^2+(1-5)^2)#
#=>sqrt((-1)^2+(-4)^2#
#=>sqrt(1+16)#
#sqrt17#
#BC=sqrt17#
Distance between #AC#
#x_1=7,x_2=3,y_1=6,y_2=1#
#AC=sqrt((3-7)^2+(1-6)^2)#
#=>sqrt((-4)^2+(-5)^2#
#=>sqrt(16+25)#
#=>sqrt41#
#AC=sqrt41#
Perimeter of a triangle is the sum of its #3# sides, that #AB+BC+AC.#
#Perimeter=sqrt10+sqrt17+sqrt41#