---

=$B$2*((D2-$A$3)*(D2-$A$4))/(($A$2-$A$3)*($A$2-$A$4)) + $B$3*((D2-$A$2)*(D2-$A$4))/(($A$3-$A$2)*($A$3-$A$4)) + $B$4*((D2-$A$2)*(D2-$A$3))/(($A$4-$A$2)*($A$4-$A$3))