A rhombus shaped field has green grass for 18 cows to graze. If each side of the rhombus is 30 m and its longer diagonal is 48 m, how much area of grass field will each cow be getting?

Join the diagonal AC of quadrilateral ABCD.
Here, the sides of triangle ABC are a = 30 m, b = 30 m and c = 48 m.
So, the semi-perimeter of triangle
S = a + b + c/2 = 30 + 30 + 48/2 = 108/2 = 54 m.
Therefore, area of triangle = √s(s – a)(s -b)(s -c)
= √54(54 -30)(54 -30)(54 -48) = √54(24)(24)(6) = √186624 = 432 m²
Hence, area of quadrilateral = 2 × 432 = 864 m²
Therefore, the area grazed by each cow = Total area/number of cows = 864/18 = 48 m²