Matematika kelas 9 | Kesebangunan Segitiga - soal (1)
Summary
TLDRIn this educational video, viewers are introduced to the concept of congruence in triangles. The presenter uses a visual approach to compare two triangles, ABC and CDE, and demonstrates how to determine the length of side EB. By showing that the triangles are congruent due to equal corresponding angles and sides, the video guides the audience through a step-by-step calculation to find the unknown side length. The presenter encourages engagement by asking viewers to like, comment, and share the video, fostering a community of learners.
Takeaways
- 📚 The video is an educational tutorial focused on the concept of similarity in triangles.
- 🔍 The presenter introduces two triangles, ABC and CDE, and explains that they are similar because they have equal corresponding angles.
- 📏 The video aims to determine the length of side EB in triangle CDE.
- 🎨 The presenter suggests drawing both the larger and smaller triangles to visualize the problem.
- 📐 The presenter uses the properties of similar triangles to set up a proportion between corresponding sides.
- ✅ The sides AB and DE, and BC and EC are compared to establish the proportion.
- 🔢 The presenter provides the known measurements: AB is 7 cm, BC is 6 cm, and EC is 5 cm.
- 🧮 A mathematical calculation is performed to find the unknown length of EB by using the proportion of the sides.
- 📉 The calculation involves cross-multiplication and simplification to solve for EB.
- 📝 The final result is that the length of EB is calculated to be 2.4 cm.
- 👍 The video encourages viewers to like, comment, share, and subscribe for more educational content.
Q & A
What is the main topic of the video?
-The main topic of the video is to learn about the similarity of triangles.
What is the first step suggested in the video to determine the similarity of triangles?
-The first step is to observe and compare the angles of the triangles to establish that they are similar because they have equal angle measures.
Why are triangles ABC and CDE considered similar in the video?
-Triangles ABC and CDE are considered similar because they have corresponding angles that are equal, which means they have the same shape.
What is the purpose of drawing two triangles in the video?
-The purpose of drawing two triangles is to visually compare their sides and angles to determine their similarity.
What is the length of side AB mentioned in the video?
-The length of side AB is mentioned as 7 centimeters.
What is the length of side CD mentioned in the video?
-The length of side CD is mentioned as 5 centimeters.
What is the length of side CE mentioned in the video?
-The length of side CE is mentioned as 6 centimeters.
What is the method used in the video to find the length of side EB?
-The method used to find the length of side EB is by setting up a proportion based on the similarity of triangles and using the known side lengths to solve for the unknown side.
What is the final calculated length of side EB according to the video?
-The final calculated length of side EB is 2.4 centimeters.
How does the video encourage viewers to engage with the content?
-The video encourages viewers to like, comment, and share the video to promote learning and sharing among peers.
What is the significance of the phrase 'sebangun' used in the video?
-The phrase 'sebangun' is used to describe the similarity of triangles, indicating that they have the same shape due to having equal angles.
Outlines
📐 Geometry Lesson: Determining the Length of Side EB in Similar Triangles
This paragraph introduces a geometry lesson focused on determining the length of side EB in two similar triangles, ABC and CDE. The lesson begins with a call to action for viewers to subscribe to Martin's channel. The instructor explains that the triangles are similar because they share corresponding angles of equal measure. The process to find the length of EB involves first drawing the triangles and then comparing the sides of the larger triangle (ABC) with the smaller one (CDE). The instructor sets up a proportion using the known side lengths (AB and DE) and the unknown side length (EB). The calculation involves setting up the proportion AB/DE = CB/CE, where CB is the sum of C and FB, and solving for FB. The instructor then demonstrates the calculation, which results in EB being 2.4 cm. The lesson concludes with an invitation for viewers to like, comment, and share the video if they have questions or want to learn more.
🤝 Encouraging Collaboration and Learning Together
The second paragraph serves as a conclusion to the video, emphasizing the importance of sharing knowledge and learning together. It encourages viewers to engage with the content by liking and sharing the video with friends. The instructor expresses gratitude and looks forward to meeting the viewers in the next video, suggesting a series of educational content where each video builds upon the previous one.
Mindmap
Keywords
💡Congruence
💡Triangles
💡Angles
💡Side Length
💡Proportional Reasoning
💡Corresponding Sides
💡Solving for Unknown
💡Subscription
💡Likes and Shares
💡Educational Content
Highlights
Introduction to the concept of similarity in triangles
Invitation to subscribe to the channel for more educational content
Presentation of two triangles ABC and CDE to be analyzed for similarity
Explanation of the criteria for triangle similarity based on equal angles
Identification of corresponding angles and sides for the triangles ABC and CDE
Introduction of the problem to determine the length of side EB
Step-by-step approach to solving the problem by comparing sides of similar triangles
Use of proportionality to relate the sides of the larger triangle to the smaller one
Calculation of the unknown side length using the given side lengths and proportionality
Explanation of the algebraic process to solve for the unknown side length
Final calculation resulting in the length of side EB being 2.4 cm
Encouragement for viewers to like, comment, and share the video for educational purposes
Expression of gratitude and anticipation for the next video
Transcripts
halo halo met in the sini di video kali
ini kita akan belajar kesebangunan dari
bangun segitiga ya Nah seperti biasa
sebelum video ini saudara tekan bagi
temen temen yang belum subscribe
silahkan subscribe dulu ya channel
Martin nya terima kasih dan saya
lanjutkan jadi disini sudah ada bangun
segitiga ABC dan segitiga c d e de
pertanyaannya Tentukan panjang EB
berarti yang ini nih yang ditanyakan Nah
kalau kita lihat disini itu ada dua
segitiga kita gambar dulu ya Jadi ada
segitiga ABC dan DC dia sebangun Kenapa
sebangun karena kita lihat sudut a
dengan sudut D Dia memiliki besar yang
sama karena dia sehadap begitu juga
dengan sudut P dan sudut e-media juga
sehadap berarti
Ia memiliki besar sudut yang sama
sedangkan sudut C ini antara segitiga
ACB dengan DC dia berhimpitan berarti
juga besar sudutnya sama berarti dia
bisa dikatakan sebangun nah caranya
bagaimana pertama kita Gambar apa
namanya bangun yang besar dan yang kecil
dulu Kita lihat Coba kita perhatikan
Hai nah ini bangun segitiga yang besar
berarti ini adalah a.di sini B dan
disini C kemudian kita gambar segitiga
yang
Hai ini c d dan e karena dia sebangun ya
kemudian kita tulis Dedenya berarti lima
kemudian ce6 cm 5 cm Oke AB disini
adalah tujuh senti meter sip kemudian
langkah selanjutnya kita bandingkan
antara Sisi eh apa namanya segitiga yang
besar dengan sisi segitiga yang kecil
karena yang ditanyakan ini adalah FB
padahal apa namanya EB ini kan panjang
dari segitiga
Kwitang + EBD berarti Sisinya yaitu yang
kita bandingkan kita tulis disini
berarti CB CB Sisi segi teknik yang
besar dibanding sisi segitiga yang
sesuai dengan ini berarti c yang kecil
sama dengan ini yang diketahui nih
berarti ABS disesuaikan dengan de-100
Sisi AB banding dengan devic3 yang kecil
oke
Hai sampai sini paham ya selanjutnya CB
kita lihat CB itu kan C ditambah FB ya
kan berarti C ditambah e-wbs nah
keluarkan fb-nya dibagi C = AB dibanding
di e&c berapa cc di sini adalah 6 cm
ditambah FB yang ditanyakan dibanding 6
= AB berapa AB disini adalah tujuh
sentimeter per D berapa DL 5 cm Nah
kalau sudah seperti ini kita kalikan
silang jadi kita kalikan silang berarti
5 dikali 6 + EBD ba
A = 6 kali tuh 7 ya ya
Ayo kita tarik ke bawah like kemudian
kita kalikan 5 dengan 65 dengan EBD
berarti 5 dikali 630 ditambah lima kali
eb5 FB = 6 dikali tujuh berapa 42 ya
berarti 5eb = 42 dikurangi 32 ty5 ebs =
berapa 12 ya kan Dadi EBD
Hai Yaitu 12/5 12/5 berarti berapa 2,4
cm m ketemu ya jadi panjang fb-nya
adalah 22,4 centi meter Oke Paham ya
cara menentukan panjang fb-nya Oke video
kali ini cukup bermanfaat ya Bagi
temen-temen yang suka Silahkan di like
di comment jika ada pertanyaan boleh
di-share ke teman-teman semuanya
sehingga kita bisa sharing dan belajar
bersama Terima kasih Sampai ketemu di
video selanjutnya
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