△ABC是等边三角形.
∵a2+b2+c2=ab+bc+ac,
∴2a2+2b2+2c2=2ab+2bc+2ac,
a2-2ab+b2+a2-2ac+c2+b2-2bc+c2=0,
∴(a-b)2+(a-c)2+(b-c)2=0,
∴a=b=c.
∴△ABC是等边三角形.
△ABC是等边三角形.
∵a2+b2+c2=ab+bc+ac,
∴2a2+2b2+2c2=2ab+2bc+2ac,
a2-2ab+b2+a2-2ac+c2+b2-2bc+c2=0,
∴(a-b)2+(a-c)2+(b-c)2=0,
∴a=b=c.
∴△ABC是等边三角形.