Respuesta :

Answer: 69%

Step-by-step explanation:

10 cm

Find the area. [tex]A=s^2[/tex]

[tex]A=(10cm)^2\\A=100cm^2[/tex]

Now calculate the area when a side is lengthened by 3 cm.

10+3=13 cm

[tex]A=s^2\\A=(13cm)^2\\A=169cm^2[/tex]

Now calculate the difference.

[tex]169-100=69[/tex]

Divide it by the original number (100) and multiply by 100

[tex]\frac{69}{100}*100=69[/tex]

This is the increase.