請教數學1題

[mega]

For a project, a square piece of cloth is folded in half and sewed together to form a rectangle that has a perimeter of 36 centimeters. What was the area in square centimeters of the piece of cloth before it was folded?

ANS:144

PP得題目,我不知道怎麼算也不太懂題意><
感謝~~~~~~~~

[portia]

把一塊正方形的布 對折
變成一塊長方形
此長方形的周長為36cm
請問原來正方形面積為何?

設原來正方形的邊長為X
則 對折後的長方形 長邊仍為X 短邊為X/2
所以邊長 36=X+X+X/2+X/2
得X=12 正方形面積 12平方