Which expression shows the length, BC, of the base of the stand?
9 cot 70°
9 cos 70°

Answer:
Option A, 9 cot 70°
Step-by-step explanation:
ΔABC is a right angle triangle in which AC = 9 in
∠ ABC = 70°
and we have to find the length of BC ( base of the stand )
tan 70° = [tex]\frac{height}{base} =\frac{AC}{BC}[/tex]
BC = [tex]\frac{AC}{tan70}[/tex]
BC = 9 cot 70° [ [tex]\frac{1}{tan70*}[/tex] = cot 70° ]
Option A, 9 cot 70° is the answer.