The diameter splits the circle into 2 equal halves by going through the midpoint of the circle. The two halves are called semicircles.
Answer:

Step-by-step explanation:
You are correct down to the part where you add the partial results:

Is it for greatest common factor or least common factor
It depends on what did you mean by saying perfect square. If I've understood it correctly, I can help you with a part of your problem. The squares of mod <span>9</span><span> are </span><span><span>1</span><span>,4,7</span></span><span> which are came from </span><span><span>1,2,</span><span>4.</span></span><span> </span>Addition of the given numbers are 2,3,5,6, 8, which are exactly the part of your problem. This number, which is not shown as squares Mod 9, and thus doesn't appear as a sum of digits of a perfect square. I hope you will find it helpful.
Step-by-step explanation:
First let us suppose the missing number x
I think we will cross multiply
5b2 = bx
5b2/b = bx
5b = x