khó đọc quá:))

Bài 3: 

a: Gọi OK là khoảng cách từ O đến AB

Suy ra: K là trung điểm của AB

hay \(AK=BK=\dfrac{AB}{2}=\dfrac{8}{2}=4\left(cm\right)\)

Áp dụng định lí Pytago vào ΔOKA vuông tại K, ta được:

\(OA^2=OK^2+KA^2\)

hay OK=3(cm)

\(x\times4+\frac{1}{2}\times x=55,35\)

\(\Leftrightarrow x\times\left(4+\frac{1}{2}\right)=55,35\)

\(\Leftrightarrow x\times4,5=55,35\)

\(\Leftrightarrow x=55,35:4,5\)

\(\Leftrightarrow x=12,3\)

Vậy x= 12,3

x.4+1/2.x=55,35
x.(4+1/2)=55.35
x.9/2=55,35
x=55,35:9/2
x=12,3
vì là máy ko có dấu nhân nên thay dấu nhân là dấu chấm

1)xét tứ giác EACD

EA//DC,ED//AC

=>EACD hình bình hành

E=C=40(hai góc đối)

ta có DAC=BAC/2=60/2=30(AD là tia pg)

mà ED//AC

=>ADE=DAC=30(so le)

xét tg EAD

E+ADE+EAD=180

EAD=180-ADE-E=180-30-40=110

2)

a)xét tgAHB và tgDHB

BAH=BDH=90,ABH=HBD(BH là tia pg),BH chung

=>tgAHB=tgDHB(cạnh huyền góc nhọn)

=>AH=HD,BA=BD

b)xét tg BDE và tgBAC

BA=BD,ABC chung,BAC=BDE=90

=>tgBDE=tgBAC(gcg)

=>BE=BC

xét tg BEC

 BA/BE=BD/BC=>AD//EC(ta lét đảo)

à mik làm thiếu 

c)xét BEK

ED cắt AC tại H

mà ED vuông BC,AC vuông BE

=>H là trực tâm

lại có BK cắt AC tại H

=>BK vuông EC

xét tg vuông BKC

BM=MC

=>MK=MB(đường trung tuyến ứng cạnh huyền)(1)

xét tg vuông BAC

BM=MC

=>AM=MB(đường trung tuyến ứng cạnh huyền)(2)

từ (1)(2)=>AM=MK

e: \(\dfrac{2}{5}=\dfrac{8}{20}\)

\(\dfrac{3}{4}=\dfrac{15}{20}\)

mà 8<15

nên \(\dfrac{2}{5}< \dfrac{3}{4}\)

Cách ra nha bn ! Vs lại bài 3 hình ko cho độ thì lm sao mà lm đc đây?

1. Tom said he wanted to buy a pocket calculator for his father

2. My mother said she thought it wouldn't rain the next day

3. The nurse said the patient in that room hadn't obeyed doctor's orders

4. They said they couldn't meet me there either that day or the next day

5. Mr.Brown said their trip costed them two thousand dollars

6. He said to her that he couldn't find his hat anywhere in that room

7. My father said to them that his secretary was going to finish that job

1.   Tom said: “I want to buy a pocket calculator for my father.”

      .....................Tom said that he wanted to buy a pocket calculator for his father...........................................................................................

2.   My mother said : “I think it won’t rain tomorrow.”

      ......................My mother said that she thought it wouldn't rain the following day...........................................................................................

3.   The nurse said: “The patient in this room didn’t obey your orders, doctor.”

      ......................The nurse said to the doctor that the patient in that room hadn't obeyed his orders ...........................................................................................

4.   They said : “We can’t meet you here either today or tomorrow.”

      ............They said that they couldn't meet me there either today or tomorrow(tham khảo c4).....................................................................................................

5.   Mr. Brown said : “Our trip cost us two thousand dollars.”

      .......................Mr. Brown said that their trip cost them two thousand dollars(tham khảo c5).........................................................................................

6.   He said to her : “ I can’t find my hat anywhere in this room.”

      ..............He said to her that he couldn't find his hat anywhere in that room..................................................................................................

7.   My father said to them : “My secretary is going to finish this job.”

My father said to them that his secretary was going to finish that job