mhn di bantu butuh banget nih . mohoooooon bgt

PQ / QR = PS / ST
PQ / QR = (PQ - SQ) / ST
PQ / 15 = (PQ - 6) / 10
10 PQ = 15(PQ - 6)
10PQ = 15PQ - 90
10PQ - 15PQ = -90
-5PQ = -90
PQ = 90 / 5
PQ = 18 cm