Explanation:
since perimeter is adding all around she took the all the values and added them as above. as you can see 3√2 and 4√2 has the same square root so she added 3+4 which gave us 7√2 and then added the 2√5 but since they don't have the same square root we can't add them like we did in the other so we'll just put 7√2+2√5