Answer:
It's 3 (a + 11)
Step-by-step explanation:
I don't know if you said that the 3 was a negative but if you did then don't choose my answer.
AK = 640
Δ ABC and ΔFJK are similar. They are small triangles.
ΔCDF is the big triangle.
640 / 2 = 320 m= CF
AC & FK= 320/2 = 160 m each
2AC = CF = 2FK
2(160) = 320 = 2(160)
BG = 20 m
20/160 = x / 320
20*320 = 160x
6400 = 160x
6400/160 = x
40 = x
Area of CDF = (40 m * 320 m)/2 = 12,800 / 2= 6,400 m²