Find the measure of the angle formed between the base of the cone and a line segment that represents the slant height.

Answer:
Step-by-step explanation:
tan Ф = opposite / adjacent
Ф = arctan ( 2 / 6)
Ф = 18.4349° ( this is the angle opposite of the one wanted, or ∠C)
then
180 = 90+ 18.4349° +∠A
71.565 = ∠A