સમાન અવધિ ધરાવતા બે પ્રક્ષિપ્તકોણે પદાર્થન

${H_1} = \frac{{{u^2}{{\sin }^2}\theta }}{{2g}}$ and ${H_2} = \frac{{{u^2}{{\sin }^2}(90 - \theta )}}{{2g}} = \frac{{{u^2}{{\cos }^2}\theta }}{{2g}}$

${H_1}{H_2} = \frac{{{u^2}{{\sin }^2}\theta }}{{2g}} \times \frac{{{u^2}{{\cos }^2}\theta }}{{2g}} = \frac{{{{({u^2}\sin 2\theta )}^2}}}{{16{g^2}}} = \frac{{{R^2}}}{{16}}$

$R = 4\sqrt {{H_1}{H_2}} $