Hello,
We have to use this relation : 
He we have :

Answer:
7.4
Step-by-step explanation:
Y² + 16 = 212
<span>y</span>² <span>= 196 </span>
<span>y = -14 and 14</span>
Answer:
21.98
Step-by-step explanation:
C=2πr C=2d are the formulas of circumference so that would mean the diameter of the circle is 7 since 2 times the radius is the diameter. We then multiply the diameter 7 by PI to get 21.98