We assume your diagram shows a circle with a diameter of 58 feet, inside of which is a triangle with a base of 50 ft and a height of 27 ft.

The area you seek seems to be the difference between the area of the circle and that of the triangle.

Area of a circle is given by

area = pi*radius^2 = 3.14*(29 ft)^2 = 3.14*841 ft^2 = 2640.74 ft^2

Area of a triangle is given by

area = (1/2)*base*height = (1/2)*(50 ft)*(27 ft) = 675 ft^2

The grass area is the difference of these areas

grass area = 2640.74 ft^2 - 675 ft^2 = 1965.74 ft^2

This corresponds to choice (a).

The area you seek seems to be the difference between the area of the circle and that of the triangle.

Area of a circle is given by

area = pi*radius^2 = 3.14*(29 ft)^2 = 3.14*841 ft^2 = 2640.74 ft^2

Area of a triangle is given by

area = (1/2)*base*height = (1/2)*(50 ft)*(27 ft) = 675 ft^2

The grass area is the difference of these areas

grass area = 2640.74 ft^2 - 675 ft^2 = 1965.74 ft^2

This corresponds to choice (a).