Heron

Uses the lengths of the three sides of a triangle to calculate the area of any triangle, using Heron's formula, known since ancient times.

Enter the length of each side, followed by . Both numbers and expressions (such as √2) are permitted.

The program displays the area of the triangle.

Press to enter the side lengths of another triangle.

Test the program by entering sides of a familiar triangle, such as a 3-4-5 triangle, and checking that the calculated area is correct.

Notice what happens when the program is run with side lengths that do not form a triangle (such as 3-4-11).

There is a discussion of the use of this sort of program in the text:

Kissane, Barry & Harradine, Anthony (2000) Mathematical Interactions: Measurement,

Chatswood, NSW: Shriro, pp 19-20.