Formula for face diagonal?

Which equation and solution can be used to solve this problem? thirteen less than a number is sixteen. 13-n=16: add 13 to both sides. the answer is 29. n+13=16: subtract 13 from both sides. the answer is 3. n+16=13 subtract 13 from both sides. the answer is 3. n-13=16: add 13 to both sides. the answer is 29.

Asquare parking lot has 6,400 square meters what is the length in meters

The following division is being performed using multiplication by the reciprocal find the missing numbers is 5/12 divided by x/3 equals 5/12 times x/10 equals 1/x