Odpowiedź :
x+3x=72
4x=72/4
x=18
1 bok = 18:2=9
2 bok = 18*3=54:2 = 27
P=a*b
P=9*27=243cm²
x - jeden bok
3x - drugi bok
2(3x + x) = 72
6x + 2x = 72
8x = 72 /:8
x = 9 - pierwszy bok
3x = 3*9 = 27 - drugi bok
P = 27*9 = 243
3x - drugi bok
2(3x + x) = 72
6x + 2x = 72
8x = 72 /:8
x = 9 - pierwszy bok
3x = 3*9 = 27 - drugi bok
P = 27*9 = 243