Thread: Area - whole and decimal numbers

Hi,
I hope this is in the right post ...
I am trying to work out a simple spread sheet for pricing, based on AREA, like this:

If it costs $50 to paint 1m2 (one meter sq) then:

1m x 1m x $50 : $50
2m x 2m x $50 : $200
1.8m x 1.2m x $50 : $108
etc.

This is all good, except when I go into decimals ...

0.5m x 0.5m x $50 : $12.5 (it should be $25!)
0.9m x 0.6m x $50 : $27 (it should be $54!)

Why do I always get half of the 'real' value?
Please help!

No it shouldn't. The calculator is correct.

1/2 x 1/2 = 1/4, so 1/2 x 1/2 x 50 = 1/4 x 50. What is a quarter of 50?

9/10 x 6/10 = 54/100, so 9/10 x 6/10 x 50 = 54/100 x 50 = 54/2. What is half of 54?

Originally Posted by formik

0.5m x 0.5m x $50 : $12.5 (it should be $25!)

This is one quarter of a square metre, therefore it would require a quarter of a $50 tin, i.e 0.25 (0.5 x 0.5) of $50 = $12.5