200=4.905t, which means that t is about 6.386.

2.( 1) Let the right side of the triangle be 1×x = 10, and calculate that x is about 4.47(2)2 root number 5. Use a calculator. My mistake, but the answer is this. The calculator is at school.

3. Let its width be x meters, its length be 2x meters, the square of 2x = 400,000, and the square of x is 200,000. The nearest x is about 447.

(2) The radius of the club is r meters, the square of 5πr is -4× 5, 1×2 100π, and r is about 22.4.

4. Let a rectangular container be x meters wide, 2x meters high and 3x meters long, where m x times 2x times 3x=54, and x is about 2.

5. Let the pond radius be x meters, 2 π x = 2000 times 5, and x is about 7.98.

6. Let the radius of a circle be x meters, and the square of half is 1πx+(2x). R is about 0.60, move 1 to work out, and then the width is 0.60 times 2 = 1.20m, which is what the teacher said. It must be right. Give me more. I have difficulty typing.