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Triangle ka area

Class 6 Maths · Chapter 6: Perimeter aur Area · NCERT Ganita Prakash section 6.3

Seekho

6 cm × 4 cm ka rectangle banao. Iska area 6 × 4 = 24 sq cm hai.

Ise diagonal par kaato (kone se kone tak). Humein do triangles milte hain jo ek doosre par theek baithte hain, to har ek rectangle ka aadha hai.

24 ÷ 2 = 12 sq cm

Agar upar wala point kahin aur ho to? Seedha neeche height kheencho. Bahar ka har coral tukda A andar ke blue tukde A ke barabar hai, aur B bhi. To triangle phir bhi aadha hai!

To har triangle ke liye: area = ½ × base × height. Height base se upar wale point tak ki seedhi doori hai.

½ × 8 × 5 = 20 sq cm

Karke dekho! Upar wale point ko left-right hilao. Triangle ki shape badalti hai, par area wahi rehta hai, kyonki base aur height nahi badalte.

Zyada ya kam karna: 8 unit squares alag-alag perimeter wali shapes bana sakte hain. 4 × 2 rectangle ka perimeter 12 units hai; 8 ki lambi line ka perimeter 18 units. Area same, perimeter alag!

Sirf bahar ke kinare gino. Jahan do squares milte hain, wo kinara andar hai aur perimeter mein nahi aata. 5 squares ki is shape ka perimeter 12 units hai.

5 squares → 12 units

Yaad rakho

  • Diagonal rectangle ko do barabar triangles mein kaatta hai.
  • Triangle ka area = ½ × base × height.
  • Same area wali shapes ke perimeter alag ho sakte hain.

Quick check

Ek triangle ka base 10 cm aur height 6 cm hai. Iska area kitna hai?

  1. 16 sq cm
  2. 30 sq cm
  3. 60 sq cm
  4. 32 cm
Answer

30 sq cm. ½ × 10 × 6 = 60 ÷ 2 = 30 sq cm. Ye 10 × 6 rectangle ka aadha hai.

Socho

10 unit squares ko kinaare se kinaara jodkar sabse chhota perimeter kitna bana sakte ho? Sabse bada?

Ek answer

Sabse chhota: 14 units (5 × 2 rectangle). Sabse bada: 22 units (saare 10 squares ek line mein).

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.