Answer:
(∠C) ≅ (∠B)
∴ tan(∠B) = tan(∠C) and
Slope AB = Slope BC
Step-by-step explanation:
Part A:
To explain why the slope from point from A to B is the same with the slope from B to C with similar triangles we have;
The angle between segment AB and the vertical is the same as the angle between segment BC and the vertical - (corresponding angles)
The angle between segment AB and the horizontal is the same as the angle between segment BC and the horizontal - (corresponding angles)
The length of a segment opposite to the angle between segment AB and the horizontal is the as the length of a segment opposite to the angle between segment BC and the horizontal
Therefore, the triangle formed by A, B and the point of intersection of the vertical line from A with the horizontal line from B is congruent to the triangle formed by B, C and the point of intersection of the vertical line from B with the horizontal line from C
Which gives the angle with the horizontal at C (∠C) is congruent to the angle with horizontal B (∠B)
The slope AB = tan(∠B)
Slope BC = tan(∠C)
(∠C) ≅ (∠B)
Therefore, tan(∠B) = tan(∠C) and slope AB = Slope BC.