x^2/a + y^2/b - z^2/c == 1
x^2/a + y^2/b - 0^2/c == 1, x^2 + y^2 == 100^2, a==b
=> a == b == 10000
x^2/10000 + y^2/10000 - 0^2/c == 1, x^2 + y^2 == 140^2
=> c == 781250/3
x^2/10000 + y^2/10000 - 3 z^2/781250 = 1
We can take the x and y coordinate ranges from what we know. There's a circular tower with radius varying from 100 to 140 about the axes, plot x and y between +- 140.
You want to coax WA into giving you the ContourPlot3D of the above equation. I had issues specifying a z range.
Wolfram Alpha Plot
