$(40$ points$)$ Design a graphic user interface to multiply two numbers. The main window contains two entries to let customer to enter numbers. When the "Multiply" buteon is clicked, a Label at the bottom of the main window will display the multiplication resil. When the "Quit" button is clicked, the application is closed.

Multiplier

Number $1$: $3\mathrm{.}5$ Number $2$: $4\mathrm{.}1$

Multiply $|||$ Quit

Multiplication result is $16\mathrm{.}45$