To find the crosssectional area of a pipe with a diameter of 5 inches, use the formula in Figure 1.
Figure : Simple program formula
Before doing the calculation, rearrange the equation in the order in Figure 2.
Figure : Rearranged formula
Enter 5 in the display and press LS, x^{2}, x, RS, pi, divide, 4, then =
The result should be 19.6350 square inches.
In order to find the area of many different pipes, rather than repeat the keystrokes each time (varying only the 5 for the different diameters), put the repeatable keystrokes into a program that would look like this:
 
01

^{2}

02

X

03


04


05

4

06

=

This program assumes that the value for the diameter is in the display when the program starts to run. It calculates and displays the area. To enter this program into program memory, press the following keys. (Do not worry about the numbers that appear in the display  they are called keycodes and are explained later.) If a mistake occurs while typing a line, press backspace to erase the line, then type it over.
Keys

Display

Description

Press LS, then PRGM


Enters Program mode

Press RS, then CLPRGM

00

Clears any previously stored programs

Press LS, then x^{2}

01 51 11

Enters the keystrokes that create the program

Press x

02 55
 
Press RS, then pi

03 61 22
 
Press divide

04 45
 
Press 4

05 4
 
Press =

06 74
 
Press LS, then PRGM


Exits Program mode

Now try running this program to find the area of a pipe with a diameter of 5 inches.
Keys

Display

Description

Press C

0.0000

Clears the display

Press LS, GTO, [.], then [.]

0.0000

Goes to the first line of the program

Press 5, then R/S

19.6350

The answer
