In acute triangle $ABC$, altitudes $AD$, $BE$, and $CF$ intersect at the orthocenter $H$.  If $BD = 5$, $CD = 9$, and $CE = 42/5$, then find the length of $HE$.

[asy]
unitsize(0.3 cm);

pair A, B, C, D, E, F, H;

A = (5,12);
B = (0,0);
C = (14,0);
D = (A + reflect(B,C)*(A))/2;
E = (B + reflect(C,A)*(B))/2;
F = (C + reflect(A,B)*(C))/2;
H = extension(B,E,C,F);

draw(A--B--C--cycle);
draw(A--D);
draw(B--E);
draw(C--F);

label("$A$", A, N);
label("$B$", B, SW);
label("$C$", C, SE);
label("$D$", D, S);
label("$E$", E, NE);
label("$F$", F, NW);
label("$H$", H, SE);
[/asy]
Question:
In acute triangle $ABC$, altitudes $AD$, $BE$, and $CF$ intersect at the orthocenter $H$.  If $BD = 5$, $CD = 9$, and $CE = 42/5$, then find the length of $HE$.

[asy]
unitsize(0.3 cm);

pair A, B, C, D, E, F, H;

A = (5,12);
B = (0,0);
C = (14,0);
D = (A + reflect(B,C)*(A))/2;
E = (B + reflect(C,A)*(B))/2;
F = (C + reflect(A,B)*(C))/2;
H = extension(B,E,C,F);

draw(A--B--C--cycle);
draw(A--D);
draw(B--E);
draw(C--F);

label("$A$", A, N);
label("$B$", B, SW);
label("$C$", C, SE);
label("$D$", D, S);
label("$E$", E, NE);
label("$F$", F, NW);
label("$H$", H, SE);
[/asy]
Answer:
Let's think step by step.

user
\frac{99}{20}
In acute triangle $ABC$, altitudes $AD$, $BE$, and $CF$ intersect at the orthocenter $H$.  If $BD = 5$, $CD = 9$, and $CE = 42/5$, then find the length of $HE$.

[asy]
unitsize(0.3 cm);

pair A, B, C, D, E, F, H;

A = (5,12);
B = (0,0);
C = (14,0);
D = (A + reflect(B,C)*(A))/2;
E = (B + reflect(C,A)*(B))/2;
F = (C + reflect(A,B)*(C))/2;
H = extension(B,E,C,F);

draw(A--B--C--cycle);
draw(A--D);
draw(B--E);
draw(C--F);

label("$A$", A, N);
label("$B$", B, SW);
label("$C$", C, SE);
label("$D$", D, S);
label("$E$", E, NE);
label("$F$", F, NW);
label("$H$", H, SE);
[/asy]
train