Tolong dijawab pake cara ya no. 27 dan 29. Aku ga ngerti :-( Mksih ya❤

Ö27.) L segitiga ACD
= 1/2.a.t
= 1/2.(9+4).18
= 1/2.13.18
= 13.9
= 117 cm
L segitiga ABC
= 1/2.a.t
= 1/2.(9+4).3
= 1/2.13.3
= 13.1,5
= 19,5