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For a cylindrical pool, the inner wall and bottom of the pool should be inlaid with ceramic tiles. The diameter of the pool bottom is 8 meters, and the pool depth is 2 meters. How many square meters is the area inlaid with ceramic tiles at most
3.14×8×2+3.14×（8÷2）²
=50.24+50.24
=100.48 square meters
Answer the area that inlays ceramic tile is 100.48 square metre at most
The school built two cylindrical flower beds of the same size. The inner diameter of the bottom of the flower bed is 3 meters, and the height is 0.8 meters. There is a cylindrical fountain in the middle of the flower bed
The school built two cylindrical flower beds of the same size. The inner diameter of the bottom of the flower bed is 3 meters, and the height is 0.8 meters. There is a cylindrical fountain in the middle of the flower bed, and the perimeter of the bottom is 3.14 meters
(1) What is the floor area of the fountain?
(2) If the height of the flower bed to be filled is 0.5m (no filling in the fountain), how many cubic meters of filling is required?
(3) The school should plant a circle of ornamental trees 0.5 meters away from the fountain. In order to be beautiful, the arc length between each two trees is required to be 0.785 meters. How many ornamental trees have been planted?
(1) 1.5 times 1.5 equals 2.25. 2.25 times 3.14 equals 7.065
The school built two cylindrical flower beds of the same size. The inner diameter of the bottom of the flower bed is 3 meters, and the height is 0.8 meters. There is a cylindrical fountain in the middle of the flower bed, and the perimeter of the bottom is 3.14 meters. (1) what is the floor area of the fountain? (2) if the height of the flower bed needs to be filled is 0.5 meters (there is no filling in the fountain), (3) the school should plant a circle of ornamental trees 0.5 meters away from the fountain. For the sake of beauty, the arc length between each two trees is required to be 0.785 meters. How many ornamental trees have been planted?
1、
The radius of the fountain is 3.14 △ 3.14 △ 2 = 0.5m
So the area is 3.14 × 0.5 × 0.5 = 0.785 square meters
2、
The flower bed radius is 3 △ 2 = 1.5m
The area is 3.14 × 1.5 × 1.5-3.14 × 0.5 × 0.5 = 6.28 square meters
Therefore, filling 6.28 × 0.5 = 3.14 m3
3、
The radius of the circle where the tree is located is 0.5 + 0.5 = 1m
Perimeter 3.14 × 2 × 1 = 6.28m
So 6.28 △ 0.785 = 8
If one right side of an isosceles right triangle is in plane α, and the hypotenuse forms an angle of 30 ° with plane α, the angle degree of the other right side with plane α can be calculated
Let it be a triangle ABC
BC = √ 2Ab = √ 2Ac, AC &; the projective point of plane α, B is d
Because BC is at a 30 ° angle to plane α
So BD = BC / 2 = AB / √ 2
So sin ∠ bad = BD / AB = 1 / √ 2
So, bad = 45 degree
So the angle between the right angle side AB and the plane α is 45 degrees
A right triangle paper, subtract right angle, get a quadrilateral, then ∠ 1 + ∠ 2 = how many degrees
270
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