A square billet with an edge length of 4 decimeters is forged into a cuboid with an area of 20 square decimeters. The height of the cuboid is______ Decimeter

A square billet with an edge length of 4 decimeters is forged into a cuboid with an area of 20 square decimeters. The height of the cuboid is______ Decimeter

4 × 4 × 4 / 20 = 64 / 20 = 3.2 (decimeter). Answer: the height of this cuboid is 3.2 decimeter. So the answer is: 3.2

What is the circumference of the shadow part of the two semicircles with radius of 4cm and 5cm as shown in the figure below

In the shadow part, let the center angle of the arc of the small circle be: A, and the center angle of the arc of the large circle be: B,
So: the perimeter of shadow part = 2 + (3 / 2) PI + (A / 2) = 2 + (3 / 2) PI + arcsin (3 / 4)

What is the circumference and area of a semicircle with a diameter of 8 cm

The circumference is half of the circumference of the whole circle plus the diameter
So the perimeter is [(2pai * 8) / 2] + 8 = 8 + 8pai
Area = Pai * 8 * 8 / 2 = 32pai

Xiao Gang found a quarter of a piece of paper with a circumference of 31.4cm. What are the fan-shaped area and perimeter of the shadow

R = 31.4 / 3.14 / 2 = 5cm, sector area = 3.14 * 5 * 5 / 4 = 19.625 square cm, sector perimeter = 31.4 / 4 + 5 + 5 = 17.85cm

The radius of the big circle is 8 cm and the radius of the small circle is 5 cm. How to find the perimeter of the shadow part of the ring

The circumference of a ring is the circumference of two circles
Great circle: 2 × 8 × π = 16 π
Small circle: 2 × 5 × π = 10 π
So the circumference of the ring is 26 π
If π is 3.14, the perimeter is 81.64

1. The radius of a circle is 8 cm, the circumference of one fourth of the circle is cm, and the area of one fourth of the circle is () square cm
2. The length of a steel pipe is 6 meters, and the interception is 2 meters. The interception accounts for () of the total length, and the rest accounts for ()
3. The average of the three numbers is 6, and the ratio of the three numbers is 1 / 2:3:2 / 6:5. The largest number among the three numbers is ()
4. 20% of 8 is (); () is 4% and 3% of 5
5. 3 out of 4 out of 7 is () () 3 out of 5 is 5 out of 8

1. The radius of a circle is 8 cm, the circumference of one fourth of the circle is (12.56) cm, and the area of one fourth of the circle is (50.24) square cm
2. The length of a steel pipe is 6 meters, and 2 meters is intercepted, which accounts for 1 / 3 of the total length, and the rest accounts for 2 / 3 of the total length
3. The average of the three numbers is 6, and the ratio of the three numbers is 1 / 2:3:2 / 6:5. The largest of the three numbers is (7.5)
4. (0.024) is 4%, 3.5%
5. Three out of four out of seven is (3 / 7) (25 / 24), three out of five is 5 out of eight

The radius of a semicircle is 8 cm, its circumference is () cm, and its area is () square cm

The perimeter is 2 π R, which is about 50.24
The area is π R2, which is about 200.96

As shown in the figure, if the center angle of the circle is 30 degrees, AB is 12 cm, and point C is the midpoint of AB, what is the perimeter of the shadow?

The answer is 21.42cm

As shown in the figure, given that the diameter of the semicircle AB = 12, the center angle of the circle BC ∠ cab = 30 ° and the small shadow area is 3.26, calculate the area of the large shadow

S sector ABC = 30360 × 3.14 × 122 = 3.14 × 12 = 37.68 (square centimeter) s blank = s sector abc-s small shadow = 37.68-3.26 = 34.42 (square centimeter) s semicircle = 12 × 3.14 × (12 △ 2) 2 = 12 × 3.14 × 36 = 3.14 × 18 = 56.52 (square centimeter) s large shadow = s semicircle-s blank = 56.52-34.42

As shown in the figure, given the diameter ab of the semicircle = 12, the center angle of the circle opposite the arc BC, the angle cab = 30 degrees, and the small shadow area is 3.26, calculate the large shadow area

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