Let $x$ and $y$ be two vectors containing the $x-$coordinates and $y-$coordinates of your data:

$)$

$(7\mathrm{.}00,78\mathrm{.}51,22\mathrm{.}11,71\mathrm{.}83,46\mathrm{.}79$

use these data points to form a natural cubic spline $S(x).$

Then enter the value of $S(4\mathrm{.}5)$