Write a C# console application that computes the area of a circle,

rectangle, and the surface area of a cylinder. Display a menu showing

the three options. Allow users to input which figure

they want to see calculated. Based on the value inputted, prompt for

appropriate

dimensions and perform the calculations and display the result

accordingly $($Round the result to $3$ decimal places$).$

Write a C# console application that reads a student's grade and

displays the letter grade. It should validate the input before

processing it$,$ i$.$e$.$ if the input is negative or more than $100,$ output an

error message and stop the program. If the input is not a number,

output an error message and stop the program, too. There is one

requirement: to determine the letter grade, use $"$ switch...case $"$

$100$ grade $90A$

$90>$ grade $80B$

$80>$ grade $70C$

$70>$ grade $60D$

Grade $<mn>6</mn><mn>0</mn><mtext></mtext><mi>F</mi>$

Design a C# Windows Forms Application that calculates the

amount of profit an organization receives based on its sales. The more

sales documented, the larger the profit ratio. Allow the user to input

the total sales figure for the organization. Compute the profit based on

the following table. Display the sales, the profit ratio and profit. Your

solution should validate the entered sales information.

$$0-$ $$1000$:$3\%$

$$1000\mathrm{.}01\_$$$5000$: $3\mathrm{.}5\%$

$$5000\mathrm{.}01\_$$$10000$: $4\%$

over $$10000$: $4\mathrm{.}5\%$