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A cuboid has a length of 0.4 DM, a width of 0.3 DM, a height of 0.2 mm, a bottom area of () square decimeter, and a surface area of () square decimeter
Bottom area = length × width = 0.4 × 0.3 = 0.12 square decimeter
Surface area = sum of 6 surfaces = (0.4 × 0.3 + 0.4 × 0.2 + 0.3 × 0.2) × 2 = 0.52 square decimeter
A cuboid wood block is cut off from the upper part and the lower part with the height of 3DM and 2DM respectively, and then becomes a cube with the surface area reduced by 100dm
Find the volume of the original cuboid
Perimeter of bottom surface = 100 (2 + 3) = 20cm
Bottom side length = 20 △ 4 = 5cm
Height = 5 + 2 + 3 = 10 cm
Volume = 5 × 5 × 10 = 250 CC
If a cuboid wood block is cut off from the upper part and the lower part of the cuboid with the height of 3DM and 2DM respectively, it will become a cube. At this time, the surface area is reduced by 120 square decimeters. How many cubic decimeters is the volume of the original cuboid?
Hello
Perimeter of bottom surface = 120 (3 + 2) = 24 (decimeter)
Side length of bottom surface = 24 △ 4 = 6 (decimeter)
Cuboid original volume = 6 × 6 × (6 + 3 + 2) = 396 (cubic decimeter)
The floor of a room is paved with 60 square tiles. There are 20 black tiles and 40 white tiles. If the area of the room is 15 square meters, how many square meters are the two kinds of tiles
15 square / 60 blocks = 0.25 square / block, 40 blocks x 0.25 square / block = 10 square; 20 blocks x 0.25 square / block = 5 square. So the area of white floor is 10 square; the area of black floor is 5 square
A square with a side length of 3.14 meters can be enclosed by a piece of iron wire. If a circle is enclosed by this piece of iron wire, what is the area of the circle?
3.14 × 4 = 12.56 (m) 12.56 △ 3.14 △ 2 = 2 (m) 3.14 × 22 = 12.56 (M2) a: the area of this circle is 12.56 square meters
Use a 18.84 decimeter long wire to form a circle. The area of the circle is___ Square decimeter
The area of this circle is 28.26 square decimeters, so the answer is: 28.26 square decimeters
A piece of iron wire can just form a square with a side length of 47.1 cm. If it forms a circle, what is the area of the circle?
Circumference of circle = 47.1 × 4 = 188.4 (CM)
From the circumference formula of circle: C = 2 π R
R = C △ 2 π = 188.4 △ 2 π ≈ 30 (CM)
Area of circle: s ≈ 3.14 × 30 × 30 ≈ 2826 [square centimeter]
Use a 25.12 cm long iron wire to form a square. The area of the square is (). If you form a circle, the area of the circle is ()
The area of a square is (39.44cm & # 178;), and if it is surrounded by a circle, the area of the circle is (50.24cm & # 178;)
A square with a side length of 3.14 meters can be enclosed by a piece of iron wire. If a circle is enclosed by this piece of iron wire, what is the area of the circle?
3.14 × 4 = 12.56 (m) 12.56 △ 3.14 △ 2 = 2 (m) 3.14 × 22 = 12.56 (M2) a: the area of this circle is 12.56 square meters
Use a 12.56 meter long wire to form the largest circle. How many square meters is the area of the circle?
Radius = 12.56 △ 3.14 △ 2 = 4m
Area = 4 × 4 × 3.14 = 50.24 square meters
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