Equation has the form x2 / a2 + y2 / b2 = 1
Length of minor axis = 2b = 4 So, b = 2
So, we have x2 / a2 + y2 / 4 = 1
Since (2,1) is on the graph, 4 / a2 + 1/4 = 1
4 / a2 = 3/4
3a2 = 16
a2 = 16/3
Equation: x2 / (16/3) + y2 / 4 = 1
Simplify: 3x2 / 16 + y2 / 4 = 1
or 3x2 + 4y2 = 16