1. getting
2. cooks
3. is playing
4. will come
5. is going to rain
6. to look
7. to pay
8. watch

\(sin^2x+cos^2x=1\)

=>\(cos^2x=1-\left(\dfrac{2}{3}\right)^2=1-\dfrac{4}{9}=\dfrac{5}{9}\)

mà \(cosx>0\)(Vì \(x\in\left(0;\dfrac{\Omega}{2}\right)\))

nên \(cosx=\sqrt{\dfrac{5}{9}}=\dfrac{\sqrt{5}}{3}\)

đề bài đâu hả bạn ?

I went to+place

a. is opened

b. was being pulled down

c. had been cleaned

d. Has the rubbish been collected

Xét ΔABC có \(\dfrac{AC}{sinB}=\dfrac{AB}{sinC}\)

=>\(\dfrac{AB}{sin40}=\dfrac{8}{sin50}\)

=>\(AB=8\cdot\dfrac{sin40}{sin50}\simeq6,71\left(cm\right)\)

Xét ΔABC có \(\widehat{B}+\widehat{C}=50^0+40^0=90^0\)

nên ΔABC vuông tại A

=>\(S_{ABC}=\dfrac{1}{2}\cdot AB\cdot AC\simeq\dfrac{1}{2}\cdot8\cdot6,71=26,84\left(cm^2\right)\)

Xét ΔABC có \(\dfrac{AB}{sinC}=2R\)

=>\(2R=\dfrac{6.71}{sin40}\simeq10,44\)

=>\(R\simeq5,22\left(cm\right)\)

ΔABC vuông tại A

=>\(AB^2+AC^2=BC^2\)

=>\(BC=\sqrt{8^2+6,71^2}\simeq10,44\left(cm\right)\)

\(p=\dfrac{AB+AC+BC}{2}=\dfrac{6,71+8+10,44}{2}\simeq12,6\left(cm\right)\)

\(r=\dfrac{S}{p}=\dfrac{26.84}{12,6}\simeq2,13\left(cm\right)\)

1 D 

2 A

3 B

4 A

5 C

6 D

7 A

8 C

9 A

10 D

Phải tự làm bài để tiến bộ chớ e, mỗi lần làm là mỗi lần nhớ để lần sau làm tốt hơn đó