Respuesta :

Answer:

13 cm

Step-by-step explanation:

A^2+12^2=15^2

A^2+144=225

A^2=81

A=9

9x2=18

31-18=13 cm

Find the perimeter of a rectangle whose width is 3 cm and whose diagonal is 3 √5 cm long.

A^2+3^2=3√5^2

A^2+9=45

A^2=36

A=6

3+3+6+6=18 cm