# Geometry Calculator

## The problem

Design a Geometry class with the following methods:

• A static method that accepts the radius of a circle and returns the area of the circle. Use the following formula:
• Area = π * r * 2
• Use Math.PI for π and r for the radius of the circle
• A static method that accepts the length and width of a rectangle and returns the area of the rectangle. Use the following formula:
• Area = Length x Width
• A static method that accepts the length of a triangle’s base and the triangle’s height. The method should return the area of the triangle. Use the following formula:
• Area = Base x Height x 0.5

The methods should display an error message if negative values are used for the circle’s radius, the rectangle’s length or width, or the triangle’s base or height.

Next write a program to test the class, which displays the following menu and responds to the user’s selection:

Geometry calculator:

1. Calculate the Area of a Circle
2. Calculate the Area of a Rectangle
3. Calculate the Area of a Triangle
4. Quit

Enter your choice (1-4):

Display an error message if the user enters a number outside the range of 1 through 4 when selecting an item from the menu.

## Level Up

• Geometry calculations are common, examine if there is open source libraries or libraries within the JDK that perform these calculations. What are some reasons why you would to find a common library?
• Write unit test for Geometry class

Geometry Calculator posted by on

Tagged: java and java-exercises-beginner

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