berapa panjang PT=...cm?

PT/PR = PS/PQ
PT/(PT + 10) = (20 - 8) / 20
PT/(PT + 10) = 12 / 20
PT/(PT + 10) = 3/5
3(PT + 10) = 5 PT
3PT + 30 = 5 PT
5PT - 3PT = 30
2PT = 30
PT = 30/2
PT = 15 cm

Panjang pt adalah 15 (A)