The Total solution for NCERT class 6-12
BE and CF are two equal altitudes of atriangle ABC. Using RHS congruence rule, prove that the triangle ABC isisosceles.
In ΔBEC and ΔCFB,
∠BEC = ∠CFB (Each 90°)
BC = CB (Common)
BE = CF (Given)
∴ ΔBEC ≅ ΔCFB (By RHS congruency)
⇒ ∠BCE = ∠CBF (By CPCT)
∴ AB = AC (Sides opposite to equal angles of a triangle areequal)
Hence, ΔABC is isosceles.