The Museum of HP Calculators The Museum of HP Calculators
This program is Copyright © 1975 by Hewlett-Packard and is used here by permission. This program was originally published in "HP-55 Mathematics Programs".
This program is supplied without representation or warranty of any kind. Hewlett-Packard Company and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.
Given three sides of a triangle this program solves the triangle for the remaining parameters by the following formulas:
C = cos-1((a2+b2-c2)/2ab)
B = sin-1(b×sin(C)/c)
A = sin-1(a×sin(C)/c)
Reletter if necessary to make c the largest side. The program works in any angular mode. However, if in degree mode decimal degrees are assumed.
| Step | Instructions | Input Data/Units | Keys | Output Data/Units |
| 1 | Enter program | |||
| 2 | Store a, b, and c (c is the largest) | a | STO 1 | |
| b | STO 2 | |||
| c | STO 3 | |||
| 3 | Find the solution | BST R/S | C* | |
| R/S | B* | |||
| R/S | A | |||
| * The stack must be maintained at these positions. |
Given the following three sides:
a = 30.3
b = 40.4
c = 62.6
Solve the triangle.
Solution:
C= 123.99°
B = 32.35°
A= 23.66°
LINE CODE KEYS 00. 01. 34 RCL 02. 01 1 03. 41 ENTER↑ 04. 71 × 05. 34 RCL 06. 02 2 07. 41 ENTER↑ 08. 71 × 09. 61 + 10. 34 RCL 11. 03 3 12. 41 ENTER↑ 13. 71 × 14. 51 - 15. 34 RCL 16. 01 1 17. 34 RCL 18. 02 2 19. 71 × 20. 02 2 21. 71 × 22. 81 ÷ 23. 32 g 24. 13 cos-1 25. 84 R/S 26. 31 f 27. 12 sin 28. 34 RCL 29. 03 3 30. 81 ÷ 31. 34 RCL 32. 02 2 33. 22 x⇔y 34. 71 × 35. 31 f 36. 34 LAST X 37. 22 x⇔y 38. 32 g 39. 12 sin-1 40. 84 R/S 41. 23 R↓ 42. 34 RCL 43. 01 1 44. 71 × 45. 32 g 46. 12 sin-1 47. -00 GTO 00
R1 a R2 b R3 c
Go back to the software library
Go back to the main exhibit hall