 # Practical usage of formulas in JavaScript

Let the variable `r` with the radius of the circle be given. Using the appropriate formula, find the area of the circle and write it to the variable `s`. Print the contents of this variable to the screen.

Let the variable `a` with the side of a square be given. Find the area of the square and write it to the variable `s`. Print the contents of this variable to the screen.

Let the variables `a` and `b` with the sides of a rectangle be given. Find the area of the rectangle and write it down in the variable `s`. Print the contents of this variable to the screen.

Let the variables `a` and `b` with the sides of a rectangle be given. Find the perimeter of the rectangle and write it to the variable `p`. Print the contents of this variable to the screen.

Let the variable `tc` with the temperature in degrees Celsius be given. Use the appropriate formula to convert this temperature to degrees Fahrenheit.

Let the variable `tf` with the temperature in degrees Fahrenheit be given. Using the appropriate formula, to convert this temperature to degrees Celsius.