Area of a trapezium `(A) = 1/2 **(`Sum of parallel sides`)**(`Distance between parallel sides`)`.
For the given trapezium,
Sum of parallel sides ` = 8+6 = 14cm`
Distance between parallel sides `= 4m = 400cm`
`:.` Area of given trapezium ` = 1/2**14**400 = 2800cm^2`