Which pattern could have been used to create the sequence? 400, –200, 100, –50, 25

I believe it would be multiplied by -0.5 or -1/2.

I saw the figure of the fishpond. It composed of a rectangle and a circle. The circle is cut into two and each half is attached to the width of the rectangle making an oblong shaped fishpond.

Length of the rectangle: 2.5 inch
Width of the rectangle and diameter of the circle: 1 inch

1/2 inch equals 15 feet.

2.5 inches = 75 feet
1 inch = 30 feet

Area of a rectangle = 75 ft * 30 ft = 2,250 ft²
Area of a circle = 3.14 * (15ft)² = 3.14 * 225ft² = 706.50 ft²

Total Area = 2,250 ft² + 706.50 ft² = 2,956.50 ft²