Vẽ IK vuông góc với AC;IM vuông góc với AB
IK=IH=IM=1cm(I là gđ của 3 đường phân giác)
=>AM=AK=1 cm
▲BNI=▲BHI(cạnh huyền - góc nhọn)
=>BM=BH=2 cm
▲CKI=▲CHI(cạnh huyền - góc nhọn)
=>CK=CH=3cm
C▲ABC=AB+AC+BC=3+4+5=12cm

Ta có:

8^9+7^9+6^9+5^9+...+2^9+1^9<8^9.8=8^10<9^10

=>8^9+7^9+6^9+5^9+..+2^9+1^9<9^10

CHÚC BẠN HỌC TỐT!

1. My brother often watches TV.

2.The film is interesting that we watched it several times.

3.Students must be over sixteen.

6.There is plenty of the menu to choose.

7.I have ever the best computer.

This weekend I plan on going to a concert with one of my best friends. We’re gonna go see Maroon 5, which happens to be a rock band, and it’s down the shore in Camden, New Jersey. I plan on picking her up at her house, and then we’ll continue to go have dinner. Afterwards, we’ll drive to the arena, which is the place where the concert is held. After the concert, we’ll probably hit a lot of traffic on the way home, so we’ll just take it easy, and stop for a few breaks on the way

tổng 4 góc trong một tứ giác là 360o

mà góc yCx đối đỉnh với góc DCB

=>góc DCB= góc yCx=48o

Tứ giác ABCD có

: góc A+ góc B+ góc C+ góc D=360o

=> BCD=360o- góc A- góc C- góc D

=360o-110o-48o-70o

=132o

132o