Answer. 1.3 km
Explanation. To find the area of a square, multiply the base and the height. Because it is a square, we know that these two numbers would have to be the same. Therefore, this number has a square root. To find it, find the sq root of 1.69. The answer is 1.3. To test this, multiply 1.3 by 1.3, you get 1.69.
