kak tolong bantu no 6,7,&9, PAKEK CARANYA.

no.6
Lsgta BCD=1/2.alas.tinggi
=1/2.(8+28).15
=1/2.36.15
=18.15
=270cm^2
Lsgta ACD=1/2.alas tinggi
=1/2.8.15
=4.15
=60cm^2
Lsgta ABC=Lsgta BCD-Lsgta ACD
=270-60
=210cm^2
sedangkan keliling sgta ABC adalah
=AB+BC+CA
=17+28+39
=86cm