Answer
Find the how long should the boards be cut to .
To proof
as given
He has been given boards which are 72 inches long,
but he needs them to be 20 percent of this size.
20 % is written in the decimal form
[tex]= \frac{20}{100}[/tex]
= 0.20
20 % of the 72 inches long
=0.20× 72
= 14.4 inches
let us assume that x be the boards be cut to get the 20 percent of the 72 inches long board.
Now find out how long should the boards be cut to.
72 - x = 14.4
x = 72 - 14.4
x = 57.6 inches
Mason cuts 57.6 inches to get 20 percent of the 72 inches long board.
Hence proved