Browse · MATH
Printjmc
geometry senior
Problem
and are collinear in that order such that and . If can be any point in space, what is the smallest possible value of ?
Solution
Let the altitude from onto at have lengths and . It is clear that, for a given value, , , , , and are all minimized when . So is on , and therefore, . Thus, =r, , , , and Squaring each of these gives: This reaches its minimum at , at which point the sum of the squares of the distances is .
Final answer
110