Measurement of the branching fraction for D+ ---> K- pi+ pi+

Using the CLEO II detector at the Cornell Electron Storage Ring we have measured the ratio of branching fractions, B([ital D][sup +][r arrow][ital K][sup [minus]][pi][sup +][pi][sup +])/([ital D][sup 0][r arrow][ital K][sup [minus]][pi][sup +])=2.35[plus minus]0.16[plus minus]0.16. Our recent measurement of [ital scrB]([ital D][sup 0][r arrow][ital K][sup [minus]][pi][sup +]) then gives [ital scrB]([ital D][sup +][r arrow][ital K][sup [minus]][pi][sup +][pi][sup +])=(9.3[plus minus]0.6[plus minus]0.8)%.