Respuesta :

Answer:

r = 3x + 1

Step-by-step explanation:

The area (A) of a circle is calculated as

A = πr² ( r is the radius )

Here

πr² = π(9x² + 6x + 1) ← divide both sides by π

r² = 9x² + 6x + 1 ← perfect square

r² = (3x + 1)² , thus

r = 3x + 1