Two soap bubbles of equal radii 4 cm are touching each other with an intermediate film separating them. Surface tension of solution forming bubbles is $7\times {10}^{-2}\frac{\text{N}}{\text{m}}$. What is the distance between the centres of soap bubbles (in cm)?

Two equal circles, side-by-side, touching at one point.
From the tangency point: one long arrow straight downward and two arrows diagonally upward left and right.
Inside the left circle, a dashed horizontal line from its center to the tangency point.