Zamkatimu
Kutanthauzira koyambira
Rectangle ndi quadrilateral pomwe ngodya zonse zimakhala zofanana. Amakhalanso owongoka ndipo ali 90 °.
Kuzungulira ndi kuchuluka kwa utali wa mbali zonse za polygon. Dzina lovomerezeka ndi likulu lachilatini lachilatini P. Pansi pa "P", ndikosavuta kulemba dzina lachiwonetserocho m'malembo ang'onoang'ono kuti musasokonezedwe ndi ntchito panjira.
Ngati kutalika kwa mbalizo kuperekedwa mumagulu osiyanasiyana, sitingathe kudziwa mtunda wa rectangle. Choncho, kuti mupeze yankho lolondola, m'pofunika kutembenuza deta yonse ku gawo limodzi la muyeso.
Kodi perimeter imayeza chiyani?
- millimeter (mm);
- masentimita (cm);
- decimeter (dm);
- mita (m);
- kilomita (km) ndi mayunitsi ena autali.
M'bukuli, tiwona momwe tingawerengere kuzungulira kwa rectangle ndikusanthula zitsanzo za kuthetsa mavuto.
Fomula ya Perimeter
Mzere (P) wa rectangle ndi wofanana ndi kuchuluka kwa utali wa mbali zake zonse.
P = a + b + a + b
Chifukwa mbali zosiyana za chiwerengerochi ndi zofanana, ndondomekoyi ikhoza kuimiridwa motere:
- Mbali ziwiri: P = 2*(a+b)
- Chiwerengero cha magawo awiri a mbali: P = 2a+2b
Mbali yaifupi ndi kutalika / m'lifupi mwa rectangle, mbali yayitali ndi maziko / kutalika kwake.
Zitsanzo za ntchito
Ntchito 1
Pezani wozungulira wa rectangle ngati mbali zake ndi 5 cm ndi 8 cm.
Kusankha:
Timalowetsa zikhalidwe zodziwika u2bu5binto formula ndikupeza: P u8d 26 * (XNUMX cm + XNUMX cm) uXNUMXd XNUMX cm.
Ntchito 2
Kutalika kwa rectangle ndi 20 cm, ndipo mbali yake ndi 4 cm. Pezani mbali yachiwiri ya chithunzicho.
Kusankha:
Monga tikudziwira, P=2a+2b. Tinene kuti 4 cm ndi mbali а. Kotero mbali yosadziwika b, wochulukitsa ndi awiri, amawerengedwa motere: 2b u2d P - 20a u2d 4 cm - 12 * XNUMX cm uXNUMXd XNUMX cm.
Choncho, mbali b = 12 cm / 2 = 6 cm.
Kuthetsa mavuto
Ndipo tsopano yesetsani!
1. Mbali imodzi ya rectangle ndi 9cm ndipo ina ndi 11cm yaitali. Kodi kudziwa wozungulira?
Tisankha bwanji:
Ngati a = 9, ndiye b = 9 + 11;
Kenako b = 20 cm;
Tiyeni tigwiritse ntchito chilinganizo P = 2 × (a + b);
P = 2 × (9 + 20);
Yankho: 58cm.
2. Pezani kuzungulira kwa rectangle ndi mbali 30 mm ndi 4 cm. Fotokozani yankho lanu mu ma centimita.
Tisankha bwanji:
Sinthani 30 mm kukhala cm:
30 mm = 3 cm.
Gwiritsani ntchito chilinganizo chozungulira cha rectangle:
P \u003d 3 + 4 + 3 + 4 \u003d 14 cm.
Yankho: P = 14 cm.
3. Pezani kuzungulira kwa makona atatu ndi mbali 2 mkati ndi 300 mm. Fotokozani yankho lanu mu ma centimita.
Tisankha bwanji:
Tiyeni tisinthe kutalika kwa mbali kukhala ma centimita:
2 dm = 20 cm, 300 mm = 30 cm.
Pezani zozungulira pogwiritsa ntchito chilinganizo P = 2 × (a + b):
P \u003d 2 × (20 + 30) \u003d 2 × 50 \u003d 100 (masentimita).
Yankho: P = 100 cm.
