Question

Câu 5: Cho tam giác ABC vuông góc ở A. Biết AB=10cm và AC=15cm. Trên BC lấy trung điểm M, trên AC lấy điểm D sao cho DC = 1/3 AC. Nối B với D, A với M cắt nhau tại I. Tính diện tích tứ giác IMCD.

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Answer 1

Hình như trên

S ABC là: 15 x 10 : 2 = 75 ( cm2 )

S ABM = SAMC

S IBM = S IMC

=> S AIB = S AIC

S ABI = S IBC x 2

=> S AIB là 1 phần và S AIC là 1 phần và S IBC là 0.5 phần

S AIC là:

75 : ( 1 + 1 + 0.5 ) x 1 = 30 ( cm2 )

S IDC = 1/3 S AIC = 30 x 1/ 3 = 10 cm2

S IMC = 1 / 2 S IBC = 15x1/2 = 7.5 cm2

S IMCD = 10 + 7.5 = 17.5 cm2

Answer 2

thank you very much

Answer 3

tại sao S IBC lại là 0,5 phần ?

Answer 4

tại sao diện tích AIB=IBCx2 và tại sao S AIB và S AMC=1 phần mà trong khi đó IBC chỉ có 0.5 phần

Answer 5

Tai sao SABI bang 2 lan SIBC

Answer 6

ve trau a

Answer 7

tôi ko hiểu

Answer 8

Giỏi quá

Answer 9

dap an dung la 17,5 day

Answer 10

mik đang cần bài này , thank you bạn rất nhìu 

Answer 11

17.5 m2 dung 100%

Answer 12

11111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005

Answer 13

kho hieu qua me oi  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

Answer 14

= 17,5

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Answer 15

Diện tích tam giác ABC là: 10 x 15 : 2 = 75 (cm²)
Vì M là trung điểm BC, suy ra: 
S_ABM = S_ACM 
S_BIM = S_CIM 
Suy ra: S_ABI = S_ACI
Vì DC = 1/3 AC, suy ra: AD = 2 x CD
Suy ra: 
S_ABD = 2/3 x S_ABC (chung đường cao hạ từ B và có DC = 1/3 AC)
S_ABD = 2/3 x 75 = 50 (cm²)
S_BCD = 1/3 x S_ABC (chung đường cao hạ từ B và có DC = 1/3 AC)
S_BCD = 1/3 x 75 = 25 (cm²)
S_CDI = 1/3 x S_ACI (chung đường cao hạ từ I và có AD = 2 x CD)
Vì S_ABI = S_ACI và S_CDI = 1/3 x S_ACI. Suy ra: Tỉ số giữa S_CDI và S_ABD là 1/5
Mà S_ABD = 50 (cm²). Suy ra: S_CDI = 50 : 5 = 10 (cm²)
Vì S_BIM = S_CIM, S_BCD = 25 (cm²) và SCDI = 10 (cm²). Suy ra: S_CIM = (25 - 10) : 2 = 7,5 (cm²)
Suy ra: S_IMCD = S_ABD + S_CIM = 10 + 7,5 = 17,5 (cm²)

Answer 16

những cách giải này sao khó hiểu quá. ai làm được thì giải rõ giúp mk nhé. à ai có nhu cầu thì kb với mk nhà,mk mới tham gia nên ko biết nhiều . thanks you very much

Answer 17

Hà Anh Thư ơi Thank ko có s nhae bạn 

Answer 18

này Trần Thanh Xuân tại sao S ABI=S IBC vậy

Answer 19

17,5 m^2 đúng 100%

Answer 20

17,5 đấy!

Answer 21

17,5 cm2

Answer 22

17,5 cm2

Answer 23

17,5 cm2