Observation of nuclear scaling in the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>A</mml:mi><mml:mo>(</mml:mo><mml:mi>e</mml:mi><mml:mo>,</mml:mo><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>′</mml:mo></mml:mrow></mml:msup></mml:mrow><mml:mo>)</mml:mo></mml:math>reaction at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>x</mml:mi></mml:mrow><mml:mrow><mml:mi>B</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mo>&gt;</mml:mo><mml:mn>1</mml:mn><mml:mn/></mml:math>

The ratios of inclusive electron scattering cross sections of ${}^{4}\mathrm{He},$ ${}^{12}\mathrm{C},$ and ${}^{56}\mathrm{Fe}$ to ${}^{3}\mathrm{He}$ have been measured for the first time. It is shown that these ratios are independent of ${x}_{B}$ at ${Q}^{2}&gt;1.4{\mathrm{GeV}}^{2}$ for ${x}_{B}&gt;1.5,$ where the inclusive cross section depends primarily on the high momentum components of the nuclear wave function. The observed scaling shows that the momentum distributions at high-momenta have the same shape for all nuclei and differ only by a scale factor. The observed onset of the scaling at ${Q}^{2}&gt;1.4{\mathrm{GeV}}^{2}$ and ${x}_{B}&gt;1.5$ is consistent with the kinematical expectation that two-nucleon short range correlations (SRC) dominate the nuclear wave function at ${p}_{m}\ensuremath{\gtrsim}300\mathrm{MeV}/c.$ The values of these ratios in the scaling region can be related to the relative probabilities of SRC in nuclei with $A&gt;~3.$ Our data, combined with calculations and other measurements of the ${}^{3}\mathrm{H}\mathrm{e}/\mathrm{d}\mathrm{e}\mathrm{u}\mathrm{t}\mathrm{e}\mathrm{r}\mathrm{i}\mathrm{u}\mathrm{m}$ ratio, demonstrate that for nuclei with $A&gt;~12$ these probabilities are 4.9--5.9 times larger than in deuterium, while for ${}^{4}\mathrm{He}$ it is larger by a factor of about 3.8.