數學與統計 大學 1年以上以前

沒給角度要怎麼算啊?

Force R is the resultant of two forces P and Q. If the magnitudes of R and Q are 15 N and 7.32 N, respectively, determine (a) the magnitude of P; (9.93 N or 17.25 N) (b) the projection of R onto the direction of P. (13.6 N) B P 0 a R