nomor 4 tolong bantuannya dengan CARANYA

#mencari panjang PR
coba pkk aturan cosinus
PR² = PQ²+QR²-2PQ.QRcos120
PR² = 4²+4²-2.4.4.-1/2
PR² = 16+16-(-16)
PR² = 48
PR = √48 = 4√3

#mencari panjang RS
PR/sin<RSP = RS/sin<RPS
4√3/1/2√3 = RS/1/2√2
RS = 8.1/2√2 = 4√2