Any school district may validate and ratify the indebtedness of such school district, incurred for strictly school purposes, when the same together with all then outstanding legal indebtedness does not exceed that amount permitted for school districts in RCW
39.36.020 (1) and (3). The value of taxable property in such school district shall be ascertained as provided in Article eight, section six, Amendment 27, of the Constitution of the state of Washington.