The mean will be calculates as follows; from the formula of z-score we shall have: z=(x-μ)/σ the z-score associated with 0.5% is 0 thus 0= (8-μ)/0.4=0 solving for x we get: μ=9
So u have to add all the sides up. which will give you 6 + 6√3 + 6 +6√3 because their opposite and parallel lengths and widths are equal that gives you 12 + 12√3 so ans is 12m + 12√3m
