Using the given formula T = LS
And given the time is 3 minutes (3 x 60 = 180 seconds)and the speed is 4-1/2 inches per second:
180 = L x 4-1/2
Solve for L by dividing both sides by 4-1/2:
L = 180 / 4-1/2
L = 40
The length should be 40 inches.
Inscribe triangle RST in the square with dimensions 4×4, as shown in the figure.
from the area of this square, 4*4=16, we remove the triangles with dimensions
3×4, 2×1 and 2×4, whose side lengths are shown in the figure, and we are left with the area of triangle RST.
so

units squared
similarly,

units squared
Thus, the areas are equal.
First of 30% of 2500kcal is 750kcal
if a male consumes 2.5 kcal then 750kcal / 2.5kcal = 300
but then we would need to know how many wheat are on one hectare of land.