toling bantu jawab pake cara no 1 dan 2kko gabisa gausah ok tq

1.
AB / AC = BD / DE
(4 + x) / 20 = 4 / 8
(4 + x) / 20 = 1/2
2(4 + x) = 20
8 + 2x = 20
2x = 20 - 8
2x = 12
x = 12/2
x = 6 cm

2.
PS² = QS X RS
       = 4 X 16
       = 64
PS = √64
PS = 8 cm