Solve the following math problem efficiently and clearly:

- For simple problems (2 steps or fewer):
Provide a concise solution with minimal explanation.

- For complex problems (3 steps or more):
Use this step-by-step format:

## Step 1: [Concise description]
[Brief explanation and calculations]

## Step 2: [Concise description]
[Brief explanation and calculations]

...

Regardless of the approach, always conclude with:

Therefore, the final answer is: $oxed{answer}$. I hope it is correct.

Where [answer] is just the final number or expression that solves the problem.

Problem: Six congruent copies of the parabola $y = x^2$ are arranged in the plane so that each vertex is tangent to a circle, and each parabola is tangent to its two neighbors.  Find the radius of the circle.

[asy]
unitsize(1 cm);

real func (real x) {
  return (x^2 + 3/4);
}

path parab = graph(func,-1.5,1.5);

draw(parab);
draw(rotate(60)*(parab));
draw(rotate(120)*(parab));
draw(rotate(180)*(parab));
draw(rotate(240)*(parab));
draw(rotate(300)*(parab));
draw(Circle((0,0),3/4));
[/asy]
user