Centre is at the middle or the midpoint of the diameter.
And the formula of midpoint is

For the given question, x1=-4, y1=2, x2=2, y2=-8
So we will get

And that's the required centre .
Answer:
He should cross multiply 90 and 60, and then divide by 100. The answer is 54.
Answer:
Pythagorean theorem 
Step-by-step explanation:

Answer: B
Step-by-step explanation:
Grade must be greater than or equal to 88
Answer:
55:5
121:11
Step-by-step explanation: