Tolong jawabkan yaa :)

karena siku di A.maka B+C = 90° sin (B+C) = sin90°. ==» sin B.cosC+cosBsinC = 1 3/4 + cosBsinC=1 . maka cosB sin C = 1/4
sin(B-C)=sin B cos C-cos B sin C= (4/3)
3/4 -1/4 = (4/3) m ===»(4/3)m = 2/4. maka m = 3/8