---
title: "Volumes: Geometry"
id: 57115
type: "computer_media"
slug: "volumes-geometry"
url: "http://localhost/computer_media/volumes-geometry/"
markdown_url: "http://localhost/computer_media/volumes-geometry.md"
published_at: "2024-10-03T23:44:19+00:00"
modified_at: "2026-03-30T21:19:52+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2024/10/64_Vol.png"
excerpt: "A handy geometry tool that calculates volumes for six different 3D shapes—cone, pyramid, prism, cube, cylinder, and sphere—with a clean input loop."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 1000"
    slug: "ts1000"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts1000/"
model:
  - name: "Timex/Sinclair 1000"
    slug: "ts-1000"
    taxonomy: "model"
    url: "http://localhost/model/ts-1000/"
genre:
  - name: "Education"
    slug: "education"
    taxonomy: "genre"
    url: "http://localhost/type/education/"
  - name: "Mathematics"
    slug: "mathematics"
    taxonomy: "genre"
    url: "http://localhost/type/mathematics/"
media_contents:
  - id: 56733
    title: "Timex Sinclair Public Domain Library Tape 1002"
    type: "computer_media"
    url: "http://localhost/computer_media/timex-sinclair-public-domain-library-tape-1002/"
media_type: "Program"
mediadate: "198x"
images:
  - url: "http://localhost/wp-content/uploads/2024/10/64_Vol.png"
media_type_tags: "Education, Mathematics"
---

# Volumes: Geometry

This program calculates the volumes of six geometric shapes: cone, pyramid, prism, cube, cylinder, and sphere. The user selects a shape by typing its name, then enters the required dimensions such as area, height, radius, length, or width. Volumes are computed using standard mathematical formulas, including the built-in PI constant and the exponentiation operator (**) for the sphere formula V = (4·π·r³)/3. After displaying the result, the program waits for a keypress using a busy-loop on INKEY$ before clearing the screen and looping back for another calculation.

***

## Program Analysis

### Program Structure

The program is organized into clearly separated blocks by line-number range:

| Line range | Purpose |
| --- | --- |
| 1–30 | Title display and initialisation |
| 100–170 | Shape selection menu and input dispatch |
| 200–280 | Cone / Pyramid / Prism handler (area × height) |
| 300–350 | Cube/cuboid handler (length × width × height) |
| 400–470 | Cylinder handler (2·π·r·h) |
| 500–530 | Sphere handler (4·π·r³/3) |
| 600–660 | Result display, keypress wait, loop back |
| 700–800 | SAVE and RUN utility lines |

### Input and Dispatch

Shape selection is handled by a cascade of `IF … THEN GOTO` statements at lines `130`–`160`. If none of the recognised strings matches `X$`, line `170` loops back to `100`, effectively re-prompting without an explicit error message. The cone, pyramid, and prism cases are grouped at line `130` because they all share the same base formula (area × height), with the cone and pyramid then halved further at line `270`.

### Volume Formulas

| Shape | Formula used | Notes |
| --- | --- | --- |
| Prism | V = A × H | Correct |
| Cone / Pyramid | V = A × H / 3 | Correct (1/3 base × height) |
| Cube / Cuboid | V = L × W × H | Correct |
| Cylinder | V = 2·π·R·H | **Bug:** should be π·R²·H; missing R factor, multiplies by 2 instead |
| Sphere | V = (4·π·R³) / 3 | Correct |

### Notable Techniques

- The built-in `PI` constant is used directly in lines `460` and `530`, avoiding the need for a numeric approximation.
- The exponentiation operator `**` is used in line `530` (`R**3`) for the sphere formula, which is the standard power operator in this BASIC dialect.
- The cone/pyramid shortcut at lines `260`–`270` computes `V = A*H` first and then conditionally divides by 3, sharing code with the prism case neatly.
- A busy-loop keypress wait at line `640` (`IF INKEY$="" THEN GOTO 640`) pauses until any key is pressed before clearing the screen and recycling.
- Line numbering uses deliberate gaps (e.g. `300`, `305`, `310` …) in the cube block, suggesting the section was added or expanded after the initial numbering scheme was laid out.

### Bugs and Anomalies

The cylinder volume formula at line `460` is incorrect. It reads `LET V=2*PI*R*H`, which equals 2πrh (the lateral surface area of a cylinder, not its volume). The correct formula is V = π·R²·H, which would be written `LET V=PI*R*R*H` or `LET V=PI*(R**2)*H`.

The label in the shape prompt at line `100` says “CUBE” but the handler at lines `300`–`345` accepts three independent dimensions (length, width, height), making it a general cuboid calculator rather than a cube-only one. No validation ensures L = W = H for a true cube.

## Source Code

```
   1 REM **VOLUMES**
  10 CLEAR 
  20 PRINT "VOLUMES"
  30 PRINT 
 100 PRINT "OBJECT(CONE,PYRAMID,PRISM,CUBE,CYLINDER,SPHERE): ";
 110 INPUT X$
 120 PRINT X$
 130 IF X$="CONE" OR X$="PYRAMID" OR X$="PRISM" THEN GOTO 200
 140 IF X$="CUBE" THEN GOTO 300
 150 IF X$="CYLINDER" THEN GOTO 400
 160 IF X$="SPHERE" THEN GOTO 500
 170 GOTO 100
 200 PRINT "AREA: ";
 210 INPUT A
 220 PRINT A
 230 PRINT "HEIGHT: ";
 240 INPUT H
 250 PRINT H
 260 LET V=A*H
 270 IF X$="CONE" OR X$="PYRAMID" THEN LET V=V/3
 280 GOTO 600
 300 PRINT "LENGTH: ";
 305 INPUT L
 310 PRINT L
 315 PRINT "WIDTH: ";
 320 INPUT W
 325 PRINT W
 330 PRINT "HEIGHT: ";
 335 INPUT H
 340 PRINT H
 345 LET V=L*W*H
 350 GOTO 600
 400 PRINT "RADIUS: ";
 410 INPUT R
 420 PRINT R
 430 PRINT "HEIGHT: ";
 440 INPUT H
 450 PRINT H
 460 LET V=2*PI*R*H
 470 GOTO 600
 500 PRINT "RADIUS: ";
 510 INPUT R
 520 PRINT R
 530 LET V=(4*PI*(R**3))/3
 600 PRINT "VOLUME: ";V
 610 PRINT 
 620 PRINT 
 630 PRINT "PRESS ANY KEY TO CONTINUE"
 640 IF INKEY$="" THEN GOTO 640
 650 CLS 
 660 GOTO 10
 700 SAVE "1006%4"
 800 RUN
```