What is the Side-Angle-Side (SAS) congruence criterion.
CBSE Board and Others state Board.
9th Maths EXERCISE 7.2, Page No:124, Questions No:4.
NCERT Books for Session 2023-2024 are based on CBSE Board.
ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal (see Figure). Show that (i) Δ ABE ≅ Δ ACF (ii) AB = AC, i.e., ABC is an isosceles triangle.
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(i) In ΔABE and ΔACF,
∠AEB = ∠AFC [∵ Each 90]
∠A = ∠A [∵ Common]
BE = CF [∵ Given]
Hance, ΔABE ≅ ΔACF [∵ SAS Congruency Rule]
(ii) In ΔABE ΔACF [∵ Proved above]
AB = AC [∵ CPCT]
Hence, ΔABC is an isosceles triangle.