Question 1
(Geometry: area of a regular polygon)
A regular polygon is an n-sided polygon in which all sides are of the same length and all angles have the same degree (i.e., the polygon is both equilateral and equiangular). The formula for computing the area of a regular polygon is
area = (n * s^2) / (4 * tan(PI / n)
Here, s is the length of a side. Write a program that prompts the user to enter the number of sides and their length of a regular polygon and displays its area.
Sample Run
Enter the number of sides: 5
Enter the side: 6.5
The area of the polygon is 72.69017017488385
Question 2
(Convert letter grade to number)
Write a program that prompts the user to enter a letter grade A/a, B/b, C/c, D/d, or F/f and displays its corresponding numeric value 4, 3, 2, 1, or 0.
Sample Run 1
Enter a letter grade: B
The numeric value for grade B is 3
Sample Run 2
Enter a letter grade: b
The numeric value for grade b is 3
Sample Run 3
Enter a letter grade: T
T is an invalid grade
Question 3
(Days of a month)
Write a program that prompts the user to enter the year and the first three letters of a month name (with the first letter in uppercase) and displays the number of days in the month.
Sample Run 1
Enter a year: 2001
Enter a month: Jan
Jan 2001 has 31 days
Sample Run 2
Enter a year: 2000
Enter a month: Feb
Feb 2000 has 29 days
Sample Run 3
Enter a month: 2001
Enter a month: jan
jan is not a correct month name
Question 4
(Business: check ISBN-10)
An ISBN-10 (International Standard Book Number) consists of 10 digits: d1d2d3d4d5d6d7d8d9d10. The last digit, d10, is a checksum, which is calculated from the other nine digits using the following formula:
(d1 * 1 + d2 * 2 + d3 * 3 + d4 * 4 + d5 * 5 + d6 * 6 + d7 * 7 + d8 * 8 + d9 * 9) % 11
If the checksum is 10, the last digit is denoted as X according to the ISBN-10 convention. Write a program that prompts the user to enter the first 9 digits and displays the 10-digit ISBN (including leading zeros).
Sample Run 1
Enter the first 9 digits of an ISBN as a string: 3601267
Incorrect input. It must have exact 9 digits
Sample Run 2
Enter the first 9 digits of an ISBN as a string: 013601267
The ISBN-10 number is 0136012671
Sample Run 3
Enter the first 9 digits of an ISBN as a string: 013031997
The ISBN-10 number is 013031997X
Question 5
(Hex to binary)
Write a program that prompts the user to enter a hex digit and displays its corresponding binary number.
Sample Run 1
Enter a hex digit: B
The binary value is 1011
Sample Run 2
Enter a hex digit: b
The binary value is 1011
Sample Run 3
Enter a hex digit: T
Invalid input