bai 7 : 1 nen nha hinh chu nhat co tong do dai hai canh lien tiep la 11 m, chieu rong kem chieu dai 3 m . Hoi
a)tinh dien tich nen nha
b) nguoi ta lat bang gach men hinh vuong canh la 40 cm. Hoi phai dung bao nhieu vien gach de lat kin nen nha ( coi mach vua la khong dang ke)