Respuesta :
Answer:
Step-by-step explanation:
Given: ABC is a triangle.
To prove: BC + AC > BA
Proof: In triangle ABC, we can draw a perpendicular line segment from vertex C to segment AB. The intersection of AB and the perpendicular is called E. We know that BE is the shortest distance from B to CE and AE is the shortest distance from A to CE because of the shortest distance theorem.
Therefore, [tex]BC>BE[/tex] and [tex]AC>AE[/tex].
Now, add the inequalities, we get
[tex]BC+AC>BE+AE[/tex].
Then, [tex]BE+AE=BA[/tex] because Segment addition postulate (states that given 2 points E and F, a third point D lies on the line segment EF if and only if the distances between the points satisfy the equation ED + DF = EF)
Therefore, [tex]BA+AC>BA[/tex] by substitution.
