English

Samabahu Tribhuj

Class 7 Maths · Chapter 7: Teen Kaat'ti Lines ki Kahaani · NCERT Ganita Prakash section 7.1

Seekho

Tribhuj ke teen kone (shirsh) aur unhe jodti teen bhujaayein hoti hain. Naam shirshon se, kisi bhi kram mein: △ABC, △BCA … Iske angles ∠A, ∠B aur ∠C. Agar teeno bindu ek seedhi line par hon, to tribhuj banta hi nahi.

Samabahu tribhuj ki teeno bhujaayein barabar hoti hain. 4 cm bhuja wala banaane ke liye Kabir AB = 4 cm kheenchta hai. Sirf ruler se use C ka andaaza lagaate rehna padega. Behtar: C ko A se 4 cm aur B se 4 cm hona chahiye.

Compass se: A se 4 cm radius ka chaap kheencho: us par har bindu A se 4 cm. B se 4 cm radius ka chaap kheencho. Jahan chaap kaat'te hain, wo dono se 4 cm: wahi C. AC aur BC jodo.

AC = 4 cm (arc from A) · BC = 4 cm (arc from B)

Yahi vichaar kisi bhi bindu ke liye chalta hai jo do binduon se di doori par ho. Do barabar bhujaon wala tribhuj samadvibahu (isosceles) hai: AC = BC = 5 cm ke liye A aur B dono se 5 cm ke chaap. Do barabar vritton ke bindu aur kendra kai isosceles aur samabahu tribhuj banaate hain.

Explore: teesra shirsh khojo.

  1. C aisa lagaao ki AC = BC = 5 cm (pehle A aur B ke chaaron or 5 cm ke vritt).

Yaad rakho

  • Equilateral: teeno bhujaayein barabar; isosceles: do barabar.
  • A aur B se di doori wala bindu do chaapon ke kaat par hai.

Quick check

Do 4 cm chaapon ka kaat bindu samabahu tribhuj ka teesra shirsh kyun hai?

  1. wo A aur B dono se 4 cm hai
  2. wo A aur B ke beech mein hai
  3. wo aadhaar ke upar hai
  4. chaap hamesha samabahu banaate hain
Answer

wo A aur B dono se 4 cm hai. Dono chaapon par hone ka matlab AC = 4 cm aur BC = 4 cm.

Socho

Agar AB = 4 cm, to A aur B dono se 4 cm door kitne bindu hain?

Ek answer

Do: vritt AB ke upar aur neeche kaat'te hain, do darpan-roop samabahu tribhuj.

Practice

Teen levels (easy, medium, hard) ke naye sawaalon se practice karo, kuch hands-on, hints aur hal ke saath. Topic poora karne ke liye pichhle 5 mein se 4 sahi karo.