bán kính của hình tròn là :

        28,26 : 3,14 = 9 ( cm )

Ta thấy : 9 = 3 x 3 . Vậy bán kính hình tròn là : 3 cm

3 B
4 D
5 A
6 D
7 A
8 B
9 B
10 B

a: =43,8x(2,25+7,75)=43,8x10=438

b: =>12,25(121,3-a)=980

=>121,3-a=80

hay a=41,3

a nha

71,  is going to come

72, are going to go

73, am going to have

74,  is going to buy

75,  are going to visit

76, is going to play

77,  is going to go

78, are going to sell 

79, is going to buy

80, is going to snow

( 2 giờ 165 phút + 3 giờ) × 6 = 46,5 giờ

S 4 mặt xung quanh là : 

S cần lát là:

is buying

isn't studying

is she running

is eating

are you waiting

aren't trying

are having

are travelling

is drinking

is speaking

haven't done

have just seen - has already done

have just decided

has been

hasn't had

hasn't played

haven't had

haven't seen

have just realized

have gone

b nha