1. Because the area of triangle ① accounts for 15% of the rectangular area, the sum of the areas of triangle ② and triangles ③ and ④ is 85% of the rectangular area, so the rectangular area is S=(2 1+45.3)/85%=78 square centimeters. 2. Rectangular paper, 96 cm long. Then because the common divisor of 96 and 60 is 2, 3, 4, 6, 12, when the side length of a square with the same size is 12, it can be cut into at least 8*5=40 pieces of 3. ① 18 km/h =300 m/min, so Xiaodong is 654300 m/min. T =100/300 =1/3minutes ② If the semi-circular perimeter of the inner runway is c = 2π r = 2 * 3.14 * 35 = 219.8m, the length of the straight runway of the inner runway is (400-2/. If the outer radius is r+2, then the outer perimeter minus the inner perimeter is 2 ∏ (R+2)-2 ∏ R = 4 ∏ = 4× 3.14 =12.565. The first week: 3150 * 8/15 =15-2/15) =1050m6.80 pieces include the remaining 1/3, so the number of parts in this batch is. The radius of pulley is: r = (98.9-2 * 2.35)/2 ∏ = 15m 8. Suppose * * has x kilograms of oranges, then x-x2/5-x3/5 *1/2-x2/5 * 65438+.