Marked down 15% means the new price would be 85% of the original price ( 100%-15% - 85%)
Multiply the original price by 85%:
5250 x 0.85 = 4462.50
The new price is $4,462.50
Slope of perpendicular is -1/3.
Then equation is
y-5=(-1/3)(x+9)
Cot x= cosx/sinx =√3
tan x= 1/ √3
cos x = √2 /2
x= 45
tan45= 1
tan x= -4/3
csc x= 13/5
1/sin x = 13/5
sin x= 5/13
x=22.62
tan x= 5/12