Protractor se angle kaise naapein?

Degrees

Har angle ko ek number dene ke liye mathematicians ne gole ke centre ke chaaron or ke angle ko 360 barabar hisson mein baanta. Har hissa 1 degree hai, likhte hain 1°. Angle ka maap ye hai ki usme kitne 1° ke hisse hain: 30 hisson waala angle 30° hai.

• Poore chakkar mein 360 hisse: 360°.
• Straight angle, poore chakkar ka aadha, 180° hai.
• Right angle, straight angle ka aadha, 90° hai.

360 kyun? Kaaran poori tarah pata nahi. Rigveda, insaaniyat ke sabse purane granthon mein se ek, 360 aaron waale pahiye ki baat karta hai; India, Persia, Babylon aur Egypt ke 3,000 saal se purane calendars mein 360 din the; aur Babylon ke ganitagya 60 ke samoohon mein ginte the. Sabse badi baat, 360, 7 ko chhodkar 1 se 10 tak har number se, aur 12 aur 24 se bhi, poora bant jaata hai, isliye gola kai barabar hisson mein aasaani se bant jaata hai.

Protractor

Protractor ek aadha gola hai jo 1° ke 180 barabar hisson mein bata hota hai (kuch protractor 360° ke poore gole hote hain). Base ke sabse daayein point se shuru karke har 10° par lamba aur har 5° par madhyam nishaan hota hai, isliye 10-10 aur 5-5 karke gin sakte ho. Numbers waale protractor mein numbers ke do set hote hain: ek daayein se baayein badhta hai, doosra baayein se daayein. Isse angle kisi bhi taraf khule, naap sakte ho.

Angle naapna

1. Protractor ka centre theek vertex par rakho.
2. Protractor ko aise ghumao ki base line par ek arm 0 se guzre.
3. Dekho doosri arm scale ko kahan kaatti hai aur wo scale padho jo pehli arm par 0 se shuru hota hai.

Agar koi arm 0 par na ho, to bhi ghataakar angle nikaal sakte ho. Book ke udaharan mein arms OT aur OS bahar ke scale par 20 aur 55 se guzarti hain, isliye ∠TOS = 55° − 20° = 35°.

Reflex angle naapne ke liye unhi arms ke beech ka chhota angle naapo aur 360° se ghatao. Chhota angle 100° hai to reflex angle 260° hai.

Angle banaana

∠TIN = 30° banaane ke liye:

1. Ruler se arm IN banao.
2. Protractor ka centre I par rakho, IN ko 0 line par.
3. Usi scale par 0 se ginte hue 30 par point T lagao.
4. Ruler se I aur T jodo. ∠TIN = 30° taiyaar hai.

Aam galtiyon se bacho

Book ka ‘Mind the Mistake’ ek student ko ye galtiyan karte dikhaata hai:

• Koi arm 0 par nahi: agar doosri arm 0 par nahi hai, to ek arm ki reading galat jawab deti hai. Protractor ghumao, ya dono readings ghatao.
• Centre vertex par nahi: agar protractor ka centre arm ke sire par ya vertex ke alaawa kahin aur hai, to reading ka koi matlab nahi.
• Galat scale: bahar ke 0 par arm milaakar andar ke numbers padhne se sahi jawab ki jagah 180° minus sahi jawab milta hai.

Apna protractor banao

Kaagaz ka gola kaato, aadha modo aur crease par kaatkar semicircle banao, jiske siron par 0° aur 180° likho. Ise aadha modne par 90°; phir modne par 45° aur 135°; ek baar aur modne par har 22.5° ka nishaan milta hai. Kisi angle ko modkar aadha karna use bisect karna hai, aur crease angle bisector hai.

Kaagaz ka protractor sirf wahi angles padh sakta hai jo uski crease par padein, isliye 42° ya 116° jaise angles ke liye nishaan waala protractor chahiye. Angle ke types ke liye angles ke types dekho; textbook ke sawaalon ke liye Chapter 2 NCERT solutions dekho.