Answer:
3
Step-by-step explanation:
I'm not sure how to explain without pictures, I apologize.
m∠3 = 180 - m∠8 = 180 - 123 = 57
m∠1 = m∠3 = 57°
100 - 45 - 20 (0.2 = 20%) - 12.5 (1/8 = 12.5%) = 22.5%
The slope of AC is -0.4
Proof:
In triangles ABC and DBE,
∠DBE is common to both triangles.
AB = 2DB (D is the midpoint of the interval AB)
Also, BC = 2BE (E is the midpoint of the interval BC)
Thus triangles ABC and DBE are similar in the ratio 2:1
Since, they are similar, ∠BDE must equal ∠BAC (corresponding angles in similar triangles)
If ∠BDE = ∠BAC, DE must be parallel to AC (corresponding angles are equal along parallel lines)
Thus, the slope of AC = the slope of DE
Thus, the slope of AC is -0.4
