A 240 centimeter board is to be cut into two pieces so that the longer piece is twice as long as the shorter piece. find the length of each piece.

You need two pieces and 1 has to be 2x longer than the other

set x as the smaller piece (easier to always go with the smaller value as x)

the other piece is 2x (double in size)

your equations would be 3x=240>>> x = 60

so smaller piece / x = 60

bigger piece / 2x = 120

If the side lengths are 240, then the answer is one length is 240 and one length is 120 cm