uses crt;
var a,b,c,x,y,z,t:real;
begin
clrscr;
write('Nhap a: '); readln(a);
write('Nhap b: '); readln(b);
write('Nhap c: '); readln(c);
x:=sqrt(a*b/c)*4;
y:=sqrt(a*c/b)*4;
z:=sqrt(b*c/a)*4;
t:=x+y+z;
write('Tong cac canh cua hinh hop chu nhat: ',t:2:0);
readln
end.

uses crt;

var s1, s2, s3 : integer;

    a, b, c : real;

begin

clrscr;

readln(s1, s2, s3);

a := sqrt(s1 * s2 / s3);

b := sqrt(s1 * s3 / s2);

c := sqrt(s2 * s3 / s1);

write(a * 4 + b * 4 + c * 4 : 0 : 0);

readln

end.

________________________________

$\text{Diện tích 3 mặt lần lượt là S1, S2, S3}$

$\text{+ S1 = a × b}$

$\text{⇒ a = $\dfrac{S1}{b}$}$

$\text{⇒ b = $\dfrac{S1}{a}$}$

$\text{+ S2 = a × c}$

$\text{⇒ a = $\dfrac{S2}{c}$}$

$\text{⇒ c = $\dfrac{S2}{a}$}$

$\text{+ S3 = b × c}$

$\text{⇒ b = $\dfrac{S3}{c}$}$

$\text{⇒ c = $\dfrac{S3}{b}$}$

$\text{________________________________________}$

$\text{+ a = a ⇔ $\dfrac{S1}{b}$ = $\dfrac{S2}{c}$}$

$\text{⇒ S1 = $\dfrac{S2 × b}{c}$}$

$\text{⇒ S2 = $\dfrac{S1 × c}{b}$}$

$\text{+ b = b ⇔ $\dfrac{S1}{a}$ = $\dfrac{S3}{c}$}$

$\text{⇒ S1 = $\dfrac{S3 × a}{c}$}$

$\text{⇒ S3 = $\dfrac{S1 × c}{a}$}$

$\text{+ c = c ⇔ $\dfrac{S2}{a}$ = $\dfrac{S3}{b}$}$

$\text{⇒ S2 = $\dfrac{S3 × a}{b}$}$

$\text{⇒ S3 = $\dfrac{S2 × b}{a}$}$

$\text{________________________________________}$

$\text{+ S1 = $\dfrac{S2 × b}{c}$ = $\dfrac{S3 × a}{c}$ }$

$\text{⇒ S1 = S2 × $\dfrac{S1}{a}$ = S3  × a}$

$\text{⇒ a = $\sqrt{\frac{S1 ×S2}{S3}}$}$

$\text{+ S2 = $\dfrac{S1 × c}{b}$ = $\dfrac{S3 × a}{b}$}$

$\text{⇒ S2 = S1 × c = S3 × $\dfrac{S2}{c}$}$

$\text{⇒ c = $\sqrt{\frac{S2 × S3}{S1}}$}$

$\text{+ S3 = $\dfrac{S1 × c}{a}$ = $\dfrac{S2 × b}{a}$}$

$\text{⇒ S3 = S1 × $\dfrac{S3}{b}$ = S2 × b}$

$\text{⇒ b = $\sqrt{\frac{S1 × S3}{S2}}$}$

$\text{________________________________________}$

$\text{Tổng các cạnh = 4a + 4b + 4c}$