Calculate deformation of the truncated equilateral triangular steel pyramid. The pyramid has the height h of 156mm truncated at the top by 2mm and the base side s of 127mm. The compressive point load P is of 10,679N. Please recall that compression is considered negative. Ignore the self weight of the pyramid and consider it perfectly elastic. Young's modulus for steel can be taken as 210GPa. Give your answer in mm with five decimal places.