Answer:
<em>2pi(3x + 7)</em>
Step-by-step explanation:
In order to solve for the circumference, consider the area and circumference formulas. What is common among them? The radius. Take a look at their formulas below;
Now if the area of this circle is given to be π ( 9x^2 + 42x + 49 ) we can plug it into the area formula as " Area " and solve for r ( radius );
As you can see, π was eliminated on either side of the equation, leaving us with the simplified equation ( 9x^2 + 42x + 49 ). This expression is a perfect square. How so? Well you can rewrite the expression as ( 3x )^2 + 2 * ( 3x ) * ( 7 ) + ( 7 )^2, or ( 3x + 7 )^2;
If r = 3x + 7, let us plug it into the circumference formula as to solve for the circumference;
Solution = 2pi(3x + 7)