No it had to be 9 because AC is equal to 9 and the diagonals will both be the same length
One, if you take 48/6 you get x=8 :)
Answer:
She needs to score 78 on her next test
Step-by-step explanation:

Collect like terms;

Multiply both sides by 6;
402 + x = 480
Subtract 402 from both sides;
x = 78
The radius of circle M would be 5 millimeters.
The radius is half of the diameter