BE and CF are two equal altitudes of a triangle ABC. Using RHS congruence rule, prove that the triangle ABC is isosceles.
Given: BE and CF are two equal altitudes of a triangle ABC.
To Prove: ∆ABC is isosceles.
Proof: In right ∆BEC and right ∆CFB,
Side BE = Side CF | Given
Hyp. BC = Hyp. CB | Common
∴ ∆BEC ≅ ∆CFB | RHS Rule
∴ ∠BCE = ∠CBF | C.P.C.T.
∴ AB = AC
| Sides opposite to equal angles of a triangle are equal
∴ ∆ABC is isosceles.