Answer:
The answer is 30 m²
Explanation:
step 1
find the area of the first cross section
area1=b1*h/2
b1=8 m
h=10 m
area1=6*10/2------> 30 m²
step 2
find the area of the second cross section
area 2=b2*h/2
b2=12 m
h=10 m
area1=12*10/2------> 60 m²
step 3
find the difference in the areas of the cross sections
difference=60-30------> 30 m²