Cho hinh thang can ABCD. Day nho AB bang canh ben BC va duong cheo AC vuong goc oi canh ben AD.
a) Tinh cac goc cua hinh thang can
b)Chung minh rangg trong hnh thang can do day lon gap doi day nho
chung minh rang trong mot hinh thang khong can thi duong cheo doi dien voi goc o day lon hon thi lon hon duong cheo doi dien voi goc day nho hon
Cho tu giac abcd la hinh thang co day lon ab bang 9 cm day be cd= 3cm ad= 3cm va goc adc =120°. Goi m,n lan luot la trung diem cua ab va cd. Goi i la trung diem cua mn. Ci keo dai cat ab tai e. Chung minh tu giac amnd la hinh thang can.
Chung minh tu giac emcn la hinh chu nhat
1) duong trung binh cua hinh thang ABCD voi 2 day AB = 8cm, va CD = 10 cm co do dai la (chi minh cach lam nha)
Cho hinh thang ABCD co day lon AB bang duong cheo AC, CD2=2BC2. Tinh goc BAD
cho hinh thang can ABCD day nho AB day lon CD, AC cat BD tai O va goc AOB =60 do .goi M,N lan luot la hinh chieu cua B,C tren AC,BD; E la trung diem cua BC.CMR tam giac MNE deu
1 hinh thang co tong day be , day lon. , va chieu cao la 36cm , day be kem day lon 2cm , chieu cao kem day be 2cm , tinh dien tich hinh thang
tim 2so , biet rang thuong cua 2 so la 1,75 va hieu cua 2 so = 0,33
cho hinh thang can abcd (ab song song cd và ab<cd)canh ben dai 1 cm goc tao boi day lon va canh ben co so do bang 60 do cd=2,7 cm tinh do dai ab
1
B=5,76xA+4,24xA
tim gia tri de B nho nhat
2
1 hinh chu nhat co chu vi la 162m . Nguoi ta tang chieu dai moi ben 3m de ra 1 hinh thang can thi dien tich tang 168mvuong
ve hinh va tinh day lon hinh thang
tinh dien tich hinh thang