6.2m, 6.2m, 3.2m
the legs of an isosceles triangle are equal
let the leg be x then the base is x - 3 ( 3 smaller than a leg )
perimeter is the sum of all 3 sides, thus
x + x + x - 3 = 15.6 ( solve for x )
3x - 3 = 15.6 ( add 3 to both sides )
3x = 15.6 + 3 = 18.6
divide both sides by 3
x =
= 6.2
the sides are 6.2m, 6.2m, 3.2m