2/5= 2x7 , 5x7 = 14/35 ; 4/7=4x5 , 7x5= 20/35

Vay 2/5 va 4/7 bang 14/35 va 20/35

Chieu rong cua hinh chu nhat la:

54x1/2=27(m)

Chu vi hinh chu nhat do la:

(54+27)x2=162(m)

dien tich hinh chu nhat do la:

54x27=1458(m vuong)

D/S: 1458 m vuong 

Thuat ngu la:

la nhung tu ngu biet thi khai niem khoa hoc  va cong nghe thuong duoc su dung trong cac van ban khoa hoc , cong nghe.

An so la:

gia tri chua biet , duoc ky hieu bang mot chu cai hoac mot ki hieu dac biet.

1x2x3x4x5x6x7=5040

II la 2

minh chua co diem :((

mik chua co diem :((

Thoi gian o to di thuc te la: 3+1=4 gio

ti so giua thoi gian du dinh va thoi gian thuc di la 3:4= 3/4

Theo de bai van toc du dinh nhieu hon voi van toc thuc te la 14km/h

Tinh hieu ti:

Hieu so phan bang nhau la: 4-3=1 phan

van toc di du dinh la 14:1x4=56km/h

Quang duong CD dai la: 56x3=168km

Dap so: 168km

chuc ban hoc tot

luc ma sat la luc tiep xuc