The standard form of ellipse with vertical major axis and center at the origin is:
x^2/b^2+y^2/a^2=1, a>b
2a=length of the major axis=28
a=14
a^2=196
2b=length of minor axis=20
b=10
b^2=100
x^2/196+y^2/100=1
making y the subject we get
y=5/7(196-x²)^0.5
