The upper quotient 2 is called out against each other to exhaust the dividend. This yields the width of 11 paces. Adding the deficit of 9 paces gives the length, matching the question.

The Right-Angled Field

Now there is a right-angled field Gougu tian: a field in the shape of a right triangle, named after its two legs: the 'Gou' (base) and 'Gu' (altitude) with an area of 486 paces. It is only stated that the base Gou: the shorter leg of a right triangle is 18 paces less than the hypotenuse Xian: the longest side of a right triangle, opposite the right angle. Question: What is the length of each side?

Method: The method says: Double the area to get 972 paces as the dividend Shi: the number to be divided or from which a root is extracted. Take the difference between the hypotenuse and the base 18 paces and halve it to get 9 paces to serve as the constant linear component Zongfang: a term in traditional Chinese algebra representing the linear coefficient in a quadratic equation. Use the square root extraction method to find the base 27 paces. Add the difference of 18 paces to find the hypotenuse slant 45 paces. $\bigcirc$

Alternatively, square the base and square the hypotenuse. Subtract the two values to get a remainder of 1,296 paces as the dividend. Use the square root extraction method to obtain the altitude length of 36 paces, which matches the question.

Now there is a right-angled field with an area of 486 paces. It is only stated that the altitude Gu: the longer leg of a right triangle is 9 paces less than the hypotenuse. Question: What is the length of each amount?