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Angles ki tulna aur Rotating Arms

Class 6 Maths · Chapter 2: Lines aur Angles · NCERT Ganita Prakash section 2.6–2.7

Seekho

Jaanwar mooh thoda ya zyada kholte hain: jitna jabda ghoomta hai, angle utna bada. Do angles ki tulna ke liye ek ko trace karke doosre par rakh sakte hain, vertex milaakar. Ise superimposition kehte hain.

Agar vertex mil jaayein aur dono arms ek doosre par aa jaayein, to dono angles barabar hain: ghumaav same.

Dhyaan do! Lambi arms se angle bada nahi hota. Sirf ghumaav maayne rakhta hai. Angle A ki arms lambi hain, par angle B bada hai.

Bina trace kiye, transparent circle use kar sakte hain: uska centre vertex par rakho, arms jahan kinaare ko kaatein wahan nishaan lagao, phir doosre angle par rakhkar dekho kaunsa zyada khula hai.

Rotating arms: do straw ek paper clip se jude. Angle ke aakaar wali jhiri (slit) se sirf theek angle wali arms nikalti hain. 60° ki slit mein fit hone wala angle banao.

Yaad rakho

  • Angles ki tulna ek ko doosre par vertex milaakar rakhkar karo (superimposition).
  • Barabar angles: vertex aur dono arms ek doosre par aa jaati hain.
  • Arms ki lambai se angle ka size nahi badalta.

Quick check

Angle A ki arms 10 cm lambi hain aur thoda khula hai. Angle B ki arms 3 cm hain aur bahut zyada khula hai. Kaunsa angle bada hai?

  1. Angle A
  2. Angle B
  3. Barabar hain
Answer

Angle B. Size ghumaav par nirbhar hai, arm ki lambai par nahi. B zyada khula hai, to B bada hai.

Socho

Kya arms chhoti karke angle chhota kar sakte ho?

Ek answer

Nahi. Chhoti arms ko bhi ek-doosre par aane ke liye utna hi ghoomna padta hai, isliye angle wahi rehta hai.

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.