# Calculator programming introduction

Input the following program on a TI-83 or TI-84.

To begin, "PRGM > New > Create New". Call the program INTANG (for "interior angles"). Each of the programming functions can be access by again pressing the PRGM then either the CTL or I/O menus:

: Disp "HOW MANY SIDES"
: Disp "DOES THE POLYGON"
: Input "HAVE? ",N
: 180*(N-2)→S
: Disp "THE SUM OF THE"
: Disp "INTERIOR ANGLES:"
: Disp S

Run the program, "PRGM > INTANG". Be prepared to discuss the following questions:

- What does the
**Input** command do?
- What does the
**Store** command ("→" or "STO>") do?
- What are the two ways that
**Disp** is used?

## Additional challenges (optional)

Each of the following involves creating a new program with different inputs (information from the user) and outputs (what calculations are made with the information).

- INPUT: two angles (in degrees)

OUTPUT: third angle in a triangle (Remember that angles in a triangle need to sum to 180 degrees.)
- INPUT: two coordinate points (or four total inputs)

OUTPUT: the slope between the two points
- INPUT: the three coefficients of a quadratic equation

OUPUT: locations of the zeros using the quadratic formula