Ƙarshe jumla mai zuwa tare da zaɓi mafi kyau: yadda za a sami kewaye da trapezoid  Zaɓuɓɓuka: - Kewaye = ƙara tsawon dukkan bangarorin P = a + b1 + b2 + c x b1 - Kewaye = ƙara tsawon dukkan bangarorin P = a + b1 + b2 + c  Amsa:
Kewaye = ƙara tsawon dukkan bangarorin P = a + b1 + b2 + c