1. The area of this square is 100 square centimeter. Cut a circle with equal width around it, so that the remaining square area is 36 square centimeters, and find the width.

Square side length =√ 100= 10 m

Let the cutting width be x meters, and the equation can be listed as:

( 1 - 2x)( 10-2x)=36

2. Build a green belt around the extension line of a rectangular base with a length of 200m and a width of160m. If the area of this green belt is 65438+ 08.8% of the base area, find the width of the green belt.

Let the width of the green belt be x meters, and the equation can be listed as:

(200+2x)( 160+2x)=( 1+ 18.8%)* 200 * 160

3. Take the wall as one side, with a length of 7.5m, and then enclose the other three sides with a bamboo fence of 13m to form a rectangular small warehouse of 20m2, and find the two sides of the warehouse.

If the length of the adjacent edge of the wall is xm and the length of the opposite edge of the wall is 13-2xm, the equation can be listed:

x*( 13-2x)=30