AREAS (16K ZX-81)
by Ian Howland and Damian Clay
from ZX Computing (April/May 1985), pages 24-25

A suite of programs which can be used for any Sinclair computer, devised by
Ian Howland and Damian Clay of Avon.

These programs are a suite, either to be put individually into a 1K ZX81, or
to be put in together with the menu in a 16K ZX81 or Spectrum. Each program,
with your measurements will work out the area of the following shapes:

1 SQUARE/RECTANGLE
2 TRIANGLE
3 CIRCLE
4 SEMICIRCLE
5 RING

Each program follows the same pattern. First the screen clears and then asks
for the first measurement, it then displays the measurement given and the
programs:- SQUARE/RECTANGLE, TRIANGLE and RING ask for a second measurement.

Once all the measurements have been entered and verified, the screen is
cleared and the formulae displayed. The computer then works out the answer
and displays it.

[As listed in the magazine the program contains a bug. Line 5064 should GOTO
2 and not GOTO 10]