## Essential University Physics: Volume 1 (3rd Edition)

We know that the range is given as $R=\frac{(v_{\circ})^2}{g}$ This simplifies to: $v_{\circ}=\sqrt{Rg}$ The maximum altitude is given as $y=\frac{(v_{\circ})^2}{2g}=\frac{Rg}{2g}$ $y=\frac{R}{2}$ We plug in the known values to obtain: $y=\frac{180Km}{2}=90Km$