Answer:
Explanation:
If the overall area of the square is 30 units with a width of 6 units, all you need to do is divide 30 by 6. Or, if you add 6 till you get 30, which is much simpler.
If we start from six and count up till we get to/close to 30 without passing the number, we can do this.
6, 12, 18, 24, 30
Right on the dot of thirty! How lucky! Now we notice that while counting up, there were 5 variables (Don't know if I'm using this word correctly :\) of thirty in total. Then, if you want to double check, multiply 5 by 6 to get thirty and show proof that your answer is correct!
Good job! You survived the maths!
Anyways, here's the answer: The missing length of the 30 unit square is 5.