The perimeter of a round vegetable field is 18.84. If the perimeter is widened by 3 meters, how many square meters will the area increase compared with the original one?

The original radius is: 18.84 △ 3.14 △ 2 = 3M
Now the radius is 3 + 3 = 6 meters
So the area is increased: 3.14 × 6-178; - 3.14 × 3-178; = 84.78 square meters

The perimeter of a circular vegetable field is 15.7 meters. If 3 meters are added around, what is the perimeter of the vegetable field?

Original radius = 15.7 △ 3.14 △ 2 = 2.5m
Now = (2.5 + 3) × 2 × 3.14 = 34.54m

The perimeter of a round vegetable field is 43.96 meters. Now it is widened by 3 meters. How many meters is the perimeter and how many square meters is the area?

The radius is 7 meters,
The circumference of a circle with radius (7 + 3) = 10m is 62.8m
If the total area is 314 square meters, if the increased area is 160.14 square meters

People with a height of 6 meters can only see the image in the plane mirror several meters in front of the vertical plane mirror with a height of 1 meter? Why?

As shown in the picture. Whether you can see the image you make in the plane mirror has nothing to do with the distance between you and the plane mirror!
Assuming that the plane mirror and the human body are parallel (both perpendicular to the horizontal ground), the necessary condition is that the distance between the upper and lower sides of the plane mirror (the height of the plane mirror) is at least half of the height of the body! And the upper edge of the plane mirror is on the same horizontal line as the human eye

The 80 meter man stands two or two meters in front of the plane mirror. How high is his image in the mirror?

The size of the image in the plane mirror is equal to that of the object in front of the mirror

Xiaoming, who is 6m in length, is standing 2m away from a vertical plane mirror. He is () m away from the plane mirror in the mirror

Two meters. If it's from Xiaoming in the mirror, it's 2 + 24 meters
For example, Xiao Ming is measuring his eyesight in a 5m room. Xiao Ming sits in front of the mirror and looks at the eyesight chart in the mirror. How many meters away does Xiao Ming see the eyesight chart? It is known that Xiao Ming is 3M away from the mirror and 5m away from the mirror
5 + 5-3 equals Xiao Ming's distance in the mirror = 7. Do you understand?

There is a man whose height is 1.70m. If he wants to buy a mirror, he must be able to see his whole body

You can draw a vertical line AB to represent the person, and draw a vertical line Mn to represent the image of the person in the mirror. Because the distance between the person and the image is equidistant, draw a long vertical dotted line CD in the middle of the distance between AB and Mn to represent the mirror

The height of 1.70m people standing in front of the vertical plane mirror, in order to see their whole body image, the plane mirror should be at least long, what are the requirements of the plane mirror suspension

As shown in the figure, a, C and B represent the positions of the head, eyes and feet of a person respectively. EF is the position of the plane mirror. According to the imaging characteristics of the plane mirror, a ′ C ′ B ′ is the image of ACB, because OC = OC ', so OC = 12CC', EO = 12a ′ C ', fo = 12b ′ C', EF = 12a ′ B ′ = 12abef is the minimum length of the plane mirror, AB is the height of a person, which is half of the height of a person If the height of a person is 1.70m, the minimum length of the mirror is 0.85m. The position is as shown in the figure. The upper e point of the mirror should be at the height of the midpoint of the distance between the person's head and eyes. (Note: if the height of the plane mirror is not correct, you can't see your whole body image)

The height of 1.70m people standing in front of the vertical plane mirror, in order to see their whole body image, the plane mirror should be at least long, what are the requirements of the plane mirror suspension

Xiao Ming is 1.80m tall, and the distance between his eyes and the top of his head is 14cm. Standing in front of a vertical plane mirror, how long does it take to see his whole body?
What is the height of the mirror from the ground when it is suspended?
I'm stupid. I'd better be more specific. Please

Mirrors are at least long & nbsp;
DE=1.80/2=0.9m
Height from the ground
(1.80-0.14)/2=0.83m

The perimeter of a round vegetable field is 18.84. If the perimeter is widened by 3 meters, how many square meters will the area increase compared with the original one?