A circular flower bed is to be built in the center of a park. The area of the flower bed is 800 square meters. Xiao Fen estimated that its radius is about () (the error is not less than 1m) A circular flower bed is to be built in the center of a park. The area of the flower bed is 800 square meters. Xiao Fen estimated that its radius is about () (the error is not less than 1m)

A circular flower bed is to be built in the center of a park. The area of the flower bed is 800 square meters. Xiao Fen estimated that its radius is about () (the error is not less than 1m) A circular flower bed is to be built in the center of a park. The area of the flower bed is 800 square meters. Xiao Fen estimated that its radius is about () (the error is not less than 1m)

First of all, we should know the formula of calculating circle area: radius × radius × 3.14 = circle area
Then 800 △ 3.14 = 254.77707 √ 254.77707 = 15.961737m
15.961737 × 15.961737 × 3.14 = 800 square meters
A: the radius is 15.961737 meters. You need to make a few decimal places by yourself

As shown in the figure, the width of the "Hui" shaped road is 1 meter, and the length of the whole "Hui" shaped road is 8 meters and the width is 7 meters. A person walks along the center of the road from the entrance point a to the end point B, and he walks ()
A. 55 m B. 55.5 m C. 56 M D. 56.5 M

According to the analysis of the meaning of the topic, the distance from outside to inside is: length is 7.5, 7, 6, 5, 4, 3, 2, width is 6, 5, 4, 3, 2, 1, 0.5, so he walked 56 meters

A rectangular grassland is 16 meters long and 10 meters wide, with a stone road paved in the middle. What is the area of the grassland?

16 × (10-2) = 16 × 8 = 128 (M2); a: the area of grassland is 128 square meters