Oh, dude, you're hitting me with some math right out of the gate! Alright, so first we gotta convert those inches to feet because we're all about that square footage life. So, 30 inches is like 2.5 feet and 40 inches is like 3.33 feet. Multiply those bad boys together and you get 8.33 square feet. Math is fun... kind of.
15 square feet.
3 x 30 = 90 square feet. 1 square foot = 144 square inches (12 x 12) So 90 square feet = 12,960 square inches
51 inches wide x 30 inches long = 10.625 square feet.
7.5 square feet.
Multiply the two numbers and you get 1,800 square inches. Each square foot has 144 square inches. So you get 12.5 square feet.
30 inches by 10 feet = 25 square feet.
30 inches by 5 feet = 12.5 square feet.
5 square feet
15 square feet.
30 * 36 = 1080 square inches = 1080/144 = 7.5 sq. feet.
3 x 30 = 90 square feet. 1 square foot = 144 square inches (12 x 12) So 90 square feet = 12,960 square inches
51 inches wide x 30 inches long = 10.625 square feet.
7.5 square feet.
Approximately 23.3 square feet.
30 feet by 28 feet equals 840 square feet. 30 inches by 28 inches equals 840 square inches, or 5.833 square feet.
Area calculation: 30 inches by 30 inches = (30 x 30) square inches =900 square inches or, if you want square feet instead: 12 inches x 12 inches (1 square foot) = 144 square inches Take your 900 square inches and divide by 144 to get square feet. 900 / 144 = 6.25 square feet
Multiply the two numbers and you get 1,800 square inches. Each square foot has 144 square inches. So you get 12.5 square feet.