the standard form for a horizontal ellipse is
X^2/a^2 + y^2/b^2 = 1
Substitute 54 for b and and use (8,18) as the
point to find a
x=8
y=18
8^2/a^2 + 18^2/54^2 =1
64/a^2 + 324/2916 = 1
324/2916 reduces to 1/9
64/a^2 + 1/9 = 1
64/a^2= 1-1/9
64/a^2 = 8/9
64*9/8 = a^2
576/8 = 72
A^2 = 72
A = square root(72) = 8.485
So formula
would be x^2/72 + y^2/2916 =1
Let the cost of the shirt be y and the price by the which the shirt is sold is 2y. This means that at 15% discount, the shirt is sold at 1.7 of its original cost.
