<span>Use the formula d=sqrt[(x₂-x₁)^2+(y₂-y₁)^2] to find distance between 2 points. DE = </span><span>√17 EF = </span><span>√18 FD = </span><span>√17 See the attachment for the complete workout. Since,All the sides are not same to make an equilateral triangle. So its not an equilateral triangle</span>