if the perimeter of a square is X and the perimeter of a triangle is Y
then the side of triangle is Y/3 AND OF square is X /4
YOU MUST ESTABLISH AN EQUATION SYSTEM
I) X = 4+Y
II) X/3 = 8+Y/4
Of the equation II you obtain X , THE m.c.m IS 12
4X = 96+3Y, x = 96/4+3y/4, substitute it in the equation I
96/4 +3Y / 4 = 4 +Y ⇒ 4(96/4+3Y/4) = 4( 4+Y)
96+3Y = 16 + 4Y
96-16 = 4Y- 3Y, Y = 90, NOW X = 90+ 4 = 94 AND THIS IS THE VALUE OF THE PERIMETER OF THE TRIANGLE