Nemo yankin da'irar: dabara da misalai

Circle adadi ne na geometric; saitin maki akan jirgin da ke kwance a cikin da'irar.

Tsarin yanki

radius

Yankin da'ira (S) yayi daidai da samfurin lambar π da murabba'in radius.

S = π r ²

Da'irar radius (r) yanki ne na layi wanda ke haɗa cibiyarsa da kowane batu akan da'irar.

lura: don lissafin ƙimar lamba π ya kai 3,14.

Ta diamita

Yankin da'irar shine kashi ɗaya cikin huɗu na samfurin lambar π da murabba'in diamita:

Diamita da'irar (d) yayi daidai da radii biyu (d = 2r). Wannan sashin layi ne wanda ke haɗa maki biyu masu gaba da juna akan da'ira.

Misalan ayyuka

Aiki 1

Nemo yankin da'irar tare da radius na 9 cm.

Yanke shawara:

Muna amfani da dabarar da radius ke ciki:

S = 3,14 ⋅ (9 cm)² = 254,34 cm ba².

Aiki 2

Nemo yankin da'irar tare da diamita na 8 cm.

Yanke shawara:

Muna amfani da dabarar da diamita ya bayyana:

S = 1/4 ⋅ 3,14 ⋅ (8 cm)² = 50,24 cm ba².