a) ∆MNP là tam giác vuông, nên theo định lý Pytago ta có:

NP²=MN²+MP²=>NP=\(\sqrt{MN^2+MP^2}\)=\(\sqrt{8^2+6^2}\)=10(cm)

Ta có: MK là đường phân giác của ∆MNP =>\(\dfrac{NK}{KP}\) =\(\dfrac{MN}{MP}\) =\(\dfrac{4}{3}\)

=> \(\dfrac{NK}{4}\)=\(\dfrac{KP}{3}\)

Theo tính chất của dãy tỉ số bằng nhau, ta có:

\(\dfrac{NK}{4}\)=\(\dfrac{KP}{3}\)=\(\dfrac{NK+KP}{4+3}\)=\(\dfrac{10}{7}\)=> NK=5,71(cm); KP=4,29(cm)

b)Ta có: +=90°; ₁+=90°=> =₁

∆NQM đồng dạng ∆MQP

góc N =góc M₁

góc Q: chung

=> \(\dfrac{NQ}{QM}\)=\(\dfrac{MQ}{QP}\)=>

MQ²=NQ.QP

c) S_MNP=\(\dfrac{1}{2}\).MN.MP=\(\dfrac{1}{2}\).8.6=24(cm²)

=\(\dfrac{1}{2}\).MQ.NP=\(\dfrac{1}{2}\).MQ.10=24=>MQ=4,8(cm²)

Tam giác NMQ đồng dạng tam giác NPM

Góc Q= góc M (=90 độ)

Góc N: chung

=>\(\dfrac{NQ}{NM}=\dfrac{MQ}{PM}=\dfrac{4,8}{6}=\dfrac{4}{5}\)

=> \(\dfrac{S_{MQN}}{S_{NMP}}=\left(\dfrac{4}{5}\right)^2=\dfrac{16}{25}\)

Hình vẽ hơi xấu thông cảm nha...

n\(H_2\)=\(\dfrac{3,36}{22,4}\)=0,15(mol)

2Al + 3H₂SO₄ -> Al₂(SO₄)₃ + 3H₂

mH₂SO₄ = 0,15.98=14,7(g)

mddH₂SO₄ = 14,7:49%=30(g)

mAl₂(SO₄)₃ = 0,05.342=17,1(g)

m_Al= 0,1.27=2,7(g)

mddAl₂(SO₄)₃= 30+2,7-3,36=29,34(g)

C%= \(\dfrac{17,1}{29,34}\).100%=58,3%

a) PTHH: 2Na + 2\(H_2O\) -> 2NaOH + \(H_2\)

Quỳ tím chuyển màu xanh vì thu được muối.

b) Ta có: 2Na + 2\(H_2O\) -> 2NaOH + \(H_2\)

Ta có: AC'=\(\sqrt{AD^2+AB^2+BB'^2}\)( công thức này bạn xem lại bài 12 trang 104 sgk toán 8 tập 2)

The visitors were complaining______in the rain.

A. for waiting                                                          

B. me about waiting

C. about having to wait                                           

D. that they have to wait

Mark the letter A, B, C or D to indicate the sentence that best combines each pair of sentences in the following questions.

I strongly disapproved of your behavior. But I will help you this time.

A. Despite of my strong disapproval of your behavior, I will help you this time.

B. Despite my strong disapproval of your behavior, I will help you this time.

C. Because of your behaviour, I will help you this time.

D. Although I strongly disapproved of your behavior, but I will help you this time.