It depends on whether the area is 35 ft long by 20 ft wide or 35 miles by 20 miles or 35 inches by 20 inches. The question does not say which.
100 square feet
200 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
225 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
97.75 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
728 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
31,680 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
950 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
20 square feet.
224 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
114 square feet. To calculate square feet simply multiply length by width - the result is the area in square feet.
Area is calculated by multiplying width x length. Thus the square feet in an area 20 feet wide by 24 feet long is 20 x 24 = 480 square feet.
Multiply width by length to get the area. The answer would be 7,500 square feet.