Nemo kewayen trapezoid: dabara da ayyuka

A cikin wannan ɗaba'ar, za mu yi la'akari da yadda za a lissafta kewayen trapezoid da kuma nazarin misalai na warware matsalolin.

Formula kewaye

Matsakaicin (P) na trapezoid daidai yake da jimlar tsayin dukkan bangarorinsa.

P = a + b + c + d

• b и d - tushe na trapezoid;
• a и с – gefensa.

Perimeter na wani isosceles trapezoid

A cikin trapezoid isosceles, bangarorin suna daidai (a uXNUMXd c), wanda shine dalilin da ya sa ake kira isosceles. Ana lissafin kewaye kamar haka:

P = 2a + b + d or P = 2s + b + d

Perimeter na trapezoid rectangular

Don ƙididdige kewaye, ana amfani da wannan dabarar azaman ma'aunin sikelin trapezoid.

P = a + b + c + d

Misalan ayyuka

Aiki 1

Nemo kewayen trapezoid idan sansanonin sa sun kasance 7 cm da 10 cm kuma sassansa sun kasance 4 cm da 5 cm.

Yanke shawara:

Muna amfani da ma'auni na ma'auni, maye gurbin sanannun tsayin gefen da aka sani a ciki: P u7d 10 cm + 4 cm + 5 cm + 26 cm uXNUMXd XNUMX cm.

Aiki 2

Matsakaicin yanki na trapezoid isosceles shine 22 cm. Nemo tsawon gefen idan tushe na adadi ya kasance 3 cm da 9 cm.

Yanke shawara:

Kamar yadda muka sani, ana lissafta kewayen trapezoid isosceles ta hanyar dabara: P = 2a + b + dina а - gefe.

Tsawon sa wanda aka ninka da biyu shine: 2a = P - b - d = 22 cm - 3 cm - 9 cm = 10 cm.

Saboda haka, tsawon gefen shine: a = 10 cm / 2 = 5 cm.