Okuqukethwe
Izincazelo eziyisisekelo
Unxande uyi-quadrilateral lapho wonke ama-engeli alingana. Abuye aqonde futhi angama-90°.
Ipherimitha iyisamba sobude bazo zonke izinhlangothi zepholigoni. Igama elivunyelwe ngokuvamile liwuhlamvu lwesiLatini olukhulu P. Ngaphansi kuka "P", kulula ukubhala igama lesibalo ngezinhlamvu ezincane ukuze ungadideki emisebenzini endleleni.
Uma ubude bezinhlangothi bunikezwa ngamayunithi ahlukene, ngeke sikwazi ukuthola umjikelezo wonxande. Ngakho-ke, ukuze uthole isisombululo esifanele, kuyadingeka ukuguqula yonke idatha ibe yiyunithi eyodwa yokulinganisa.
I-perimeter ikalwa ngani?
- imilimitha (mm);
- isentimitha (cm);
- idesimitha (dm);
- imitha (m);
- ikhilomitha (km) namanye amayunithi ubude.
Kulolu shicilelo, sizocabangela indlela yokubala umjikelezo wonxande futhi sihlaziye izibonelo zokuxazulula izinkinga.
I-Perimeter Formula
Ipherimitha (P) yonxande ilingana nesamba sobude bazo zonke izinhlangothi zayo.
P = a + b + a + b
Ngenxa yokuthi izinhlangothi eziphambene zalo mfanekiso ziyalingana, ifomula ingamelwa kanje:
- Uhlangothi olukabili: P = 2*(a+b)
- Isamba samanani aphindwe kabili ezinhlangothini: P = 2a+2b
Uhlangothi olufushane ubude/ububanzi bukanxande, uhlangothi olude luyisisekelo/ubude balo.
Izibonelo zemisebenzi
Umsebenzi 1
Thola umjikelezo wonxande uma izinhlangothi zawo zingama-5 cm no-8 cm.
Isinqumo:
Sifaka esikhundleni samanani aziwayo u2bu5binto bese sithola: P u8d 26 * (XNUMX cm + XNUMX cm) uXNUMXd XNUMX cm.
Umsebenzi 2
I-perimeter ye-rectangle ingama-20 cm, kanti olunye lwezinhlangothi zalo luyi-4 cm. Thola uhlangothi lwesibili lomfanekiso.
Isinqumo:
Njengoba sazi, P=2a+2b. Ake sithi u-4 cm wuhlangothi а. Ngakho uhlangothi olungaziwa b, iphindwe kabili, ibalwa kanje: 2b u2d P - 20a u2d 4 cm - 12 * XNUMX cm uXNUMXd XNUMX cm.
Ngakho-ke, uhlangothi b = 12 cm / 2 = 6 cm.
Ukuxazululwa kwenkinga
Futhi manje zijwayeze!
1. Olunye uhlangothi lukanxande luyi-9cm kanti olunye luyi-11cm ubude. Ungayithola kanjani i-perimeter?
Sinquma kanjani:
Uma a = 9, khona-ke b = 9 + 11;
Bese b = 20 cm;
Masisebenzise ifomula P = 2 × (a + b);
P = 2 × (9 + 20);
Impendulo: 58 cm.
2. Thola i-perimeter kanxande enezinhlangothi ezingama-30 mm no-4 cm. Veza impendulo yakho ngamasentimitha.
Sinquma kanjani:
Guqula i-30 mm ibe yi-cm:
30 mm = 3 cm.
Sebenzisa ifomula ye-perimeter kanxande:
P \u003d 3 + 4 + 3 + 4 \u003d 14 cm.
Impendulo: P = 14 cm.
3. Thola i-perimeter kanxantathu enezinhlangothi ezingu-2 ngaphakathi no-300 mm. Veza impendulo yakho ngamasentimitha.
Sinquma kanjani:
Masiguqule ubude obuseceleni bube amasentimitha:
2 dm = 20 cm, 300 mm = 30 cm.
Thola i-perimeter usebenzisa ifomula P = 2 × (a + b):
P \u003d 2 × (20 + 30) \u003d 2 × 50 \u003d 100 (cm).
Impendulo: P = 100 cm.
