Hiii
SAWARASENAIII KIMI WA SHOJO NA NO? BOKU WA YARICHIN BICCHIII NO OSU DA YOOO AH

sawarasenaikimiwa⛓shojonano ✨bökùwâÿariçhiñbįcchīńoosûdàyo

omg I LOVE THIS SONG

Two sides are 3x longer than the shortest side. So, set up your problem like this.
  X = unknown length in centimeters 
3X = length of two longer sides
1X = length of short side
3x + 3x + 1x = 49
7x  = 49 
x = 7
So, two longer sides are 21 centimeters each and the short side is 7 centimeters.
  21+21+7 = 49