Answer:
The width is

Step-by-step explanation:
From the question we are told that
The width of the slit is

The wavelength of the light is

The position of the screen is

Generally angle at which the first minimum of the interference pattern the light occurs is mathematically represented as
![\theta = sin ^(-1)[(m \lambda)/(d) ]](https://img.qammunity.org/2021/formulas/physics/college/b9ymgc7r8fqjsry87ahp9waq8i53618se6.png)
Where m which is the order of the interference is 1
substituting values
![\theta = sin ^(-1)[(1 *721*10^(-9))/( 77.7*10^(-6)) ]](https://img.qammunity.org/2021/formulas/physics/college/h92nd1xbsh2r9zr2p0imbw9ze344rmhh78.png)

Now the width of first minimum of the interference pattern is mathematically evaluated as

substituting values


Now the width of the pattern's central maximum is mathematically evaluated as

substituting values

