Saturday, June 3, 2017

HP 20S and HP 21S: Triangle Program

HP 20S and HP 21S:  Triangle Program


Given three Cartesian coordinates, through points (R1, R4), (R2, R5), and (R3, R6), this program calculates:

1. The lengths of each side, represented by R7, R8, and R9.

2. The angle between lines connected by (R1, R4)-(R2, R5) and (R2, R5)-(R3, R6).  The angle is stored in R0.

3. The area of the triangle.  This is the final results shown.



The keystrokes for the HP 20S and HP 21S in this program are the same.  Store the coordinates in variables R1 through R6, then press XEQ A.

HP 20S and HP 21S Program: Triangle Program

STEP
CODE
KEY
01
61, 41, A
LBL A
02
22, 1
RCL 1
03
65
-
04
22, 2
RCL 2
05
31
INPUT
06
22, 4
RCL 4
07
65
-
08
22, 5
RCL 5
09
51, 21
>P
10
51, 31
SWAP
12
26
R/S
13
71
[ C ] Clear
14
22, 2
RCL 2
15
65
-
16
22, 3
RCL 3
17
31
INPUT
18
22, 5
RCL 5
19
65
-
20
22, 6
RCL 6
21
51, 21
>P
22
51, 31
SWAP
23
21, 8
STO 8
24
26
R/S
25
71
[ C ] (Clear)
26
22, 1
RCL 1
27
65
-
28
22, 3
RCL 3
29
31
INPUT
30
22, 4
RCL 4
31
65
-
32
22, 6
RCL 6
33
51, 21
>P
34
51, 31
SWAP
35
21, 9
STO 9
36
26
R/S
37
71
[ C ] Clear
38
22, 8
RCL 8
39
51, 11
x^2
40
75
+
41
22, 9
RCL 9
42
51, 11
x^2
43
65
-
44
22, 7
RCL 7
45
51, 11
x^2
46
74
=
47
45
÷
48
2
2
49
45
÷
50
22, 8
RCL 8
51
45
÷
52
22, 9
RCL 9
53
74
=
54
51, 24
ACOS
55
21, 0
STO 0
56
26
R/S
57
23
SIN
58
55
*
59
22, 7
RCL 7
60
55
*
61
22, 8
RCL 8
62
45
÷
63
2
2
64
74
=
65
61, 26
RTN

Example:
Inputs:
(R1, R4) = (4, 8)
(R2, R5) = (2, 3)
(R3, R6) = (3, 10)

Outputs:
R7 = 5.3852
R8 = 7.0711
R9 = 2.2361
R0 = 34.6952°
Area = 10.8374

Eddie


This blog is property of Edward Shore, 2017
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