Teorema. Agar a || b bo'lib, l1, l2 va l3 parallel to'g'ri chiziqlar a to'g'ri chiziqdan teng kesmalar ajratsa, b to'g'ri chiziqdan ham teng kesmalar ajratadi.
T a ' r i f. Ikki kesmaning nisbati deb, ular bir ismli birliklar bilan ifodalanganda, ulardan bin ikkinchisidan necha marta katta yoki kichikligini ko 'rsatuvchi ismsiz songa aytiladi. 2. Proporsional kesmalar. Ta'rif. Agar bo'lsa, u holda AB va BC, va kesmalar proporsional kesmalar deb ataladi. Bu kesmalarning uzunliklarini ifodalovchi sonlar proporsional sonlar bo’ladi. 4. Yangi mavzuni yoritish va Yangi mavzuni mustahkamlash --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
