问题 填空题

已知点G是△ABC的重心,AB=AC=5,BC=8,那么AG=_____。

答案

2.

题目分析:根据题意画出图形,连接AG并延长交BC于点D,由等腰三角形的性质可得出AD⊥BC,再根据勾股定理求出AD的长,由三角形重心的性质即可得出AG的长.

如图所示:连接AG并延长交BC于点D,

∵G是△ABC的重心,AB=AC=5,BC=8,

∴AD⊥BC,BD=BC=×8=4,

∴AD==3,

∴AG=AD=×3=2.

故答案为:2.

阅读理解

阅读理解。

     People use money to buy food, books, bicycles and hundreds of other things which they need.  When

they work, they usually get paid in money.

     Most of the money used today is made of metal or paper. But in ancient times people used all kinds

of things as money. One of the first kinds of money was shells.

     In China, cloth and knives were used as money. Elephant tusks, monkey tails and salt were used in

some parts of Africa. Rice was also a kind of money used by the ancient in some islands.  Cows and

other animals were used as money, too.

     The first copper coins were made in china.  They were round and had a square hole in the center.

Different countries have used different metals (金属 ) as their money. Later, some countries began to

make coins of gold (金) and silver (银).

     But both gold and silver were heavy to carry when people needed a lot of coins to buy something

expensive. The Chinese were the first to use paper money. The first paper money looked more like a

note than the paper money used today.

Money has had an interesting history from the days of shell money till today.

1. People use money to buy______ .

A. food

B. bicycles

C. all the things they need

2. they usually get paid in money______ .

A. When people buy things

B. When people have holidays

C. When people work

3. In ancient times, people use as money______ .

A. cloth and knives

B. shells

C. all kinds of things

4. The first coins were made of______ .

A. gold

B. copper

C. paper

5. The first paper notes were used in ______ .

A. China

B. Africa

C. some islands

单项选择题