As shown in the figure, the area of the shadow part is 12 square centimeters. How many square centimeters is the area of the blank part?
12 × 2 / 3 = 8 (CM) 3.14 × (8 / 2) 2 / 2 + 3 × 8-12 = 3.14 × 16 / 2 + 3 × 8-12 = 25.12 + 24-12 = 37.12 (square cm) a: the area of the blank part is 37.12 square cm
How many square centimeters is the area of a 40 cm long and 20 cm wide paper folded twice?
At least two
Fold twice in the long direction: = 20 * 40 / 4 = 200 square centimeter
Fold twice in the direction of width: = 40 * 20 / 4 = 200 square centimeter
Fold once in the long direction, fold once in the wide direction: = (40 / 2) * (20 / 2) = 200 square centimeters
The area of a piece of paper is 4 / 5 square meters. After folding it in half, the area of one part is () square meters;
After two fold, the area of one share is () square meters; after three fold, the area of one share is () square meters
The area of a piece of paper is 4 / 5 square meters. After one fold, the area of one piece of paper is (2 / 5) square meters;
After two fold, the area of one share is (1 / 5) square meters
After three fold, the area of one share is (1 / 10) square meters