√(1/2-2/3)²+√(2/3-3/4)²+√(3/4-4/5)²
=√(-1/6)²+√(-1/12)²+√(-1/20)²
=|-1/6|+|-1/12|+|-1/20|
=1/6+1/12+1/20
=1/4+1/20
=6/20
=3/10
√(1/2-2/3)²+√(2/3-3/4)²+√(3/4-4/5)²
=√(-1/6)²+√(-1/12)²+√(-1/20)²
=|-1/6|+|-1/12|+|-1/20|
=1/6+1/12+1/20
=1/4+1/20
=6/20
=3/10