Remember that the input command reads strings. You have to convert strings to integers (whole numbers) or floats (decimals) if you want to use them to perform calculations.

## Examples

1) Write a program that prompts the user to enter the length and width of a rectangle. Output the area of the rectangle

length = int(input("Enter the length of the rectangle")) width = int(input("Enter the width of the rectangle")) area = length*width print("The rectangle has an area of " + str(area))

2) To convert miles to kilometers, you multiply the number of miles by 1.609. Write a program that prompts the user to enter the number of miles, and then output the answer converted to kilometers

Note the use of float as a user may input 12.5 miles, for example.

miles = float(input("Enter the number of miles")) kilometers = miles * 1.609 print(str(miles) + " miles = " + str(kilometers) + " kilometers")

## Exercise

- Write a program with two variables, length and width, that outputs the perimeter of a rectangle. Test it with length = 5 and width = 4.
- At the time of writing, the exchange rate for pounds to euros is 1 GBP = 1.19984 Euros. Write a program that will convert pounds to euros. Test it using the data GBP4.50 (Don’t forget to convert the input to a float!)
- Now write a program to convert euros to pounds. Test it using the data Euro 7.40
- Prompt the user to input a number. Output the square of that number.
- Prompt the user to input two numbers. Output the average of those two numbers.
- Prompt the user to input three numbers. Output the sum and the average of those three numbers.
- Assume pi = 3.1415. Prompt the user to input the radius of a circle. Output the circumference and the diameter of that circle

## Extension: Fahrenheit to Celsius

Here are the formulas to convert from Fahrenheit to Celsius and back again.

°F to °C Deduct 32, then multiply by 5, then divide by 9 °C to °F Multiply by 9, then divide by 5, then add 32

- Now write a program to convert Celsius to Fahrenheit. Use the test data to check your program.
- Write a program to convert Fahrenheit to Celsius. Again, use the test data below to check your program.

### Test data

C | F |
---|---|

0 | 32 |

12 | 54 |

100 | 212 |

-3 | 27 |

-18 | 0 |

-23 | -10 |