Quadri-, quadru-, quadr-is a Latin prefix related to the verb quadrare âto make squareâ, quadratus âsquareâ etc. Quad is simply an English shortening of quadrangle, quadruplet etc. So quadri-and quad are actually the same word.
Seattle, WA Sales Tax Rate. The current total local sales tax rate in Seattle, WA is 9.600% . The December 2014 total local sales tax rate was 9.500% .
1 Counties and cities can charge an additional local sales tax of up to 3.1%, for a maximum possible combined sales tax of 9.6%.  Washington has 726 special sales tax jurisdictions with local sales taxes in addition to the state sales tax.