Answer:
Monica painted
of the frame blue.
Step-by-step explanation:
Monica has a 24-inch square frame.There are 4 equal sides. She paints 3/4 of one side of the frame blue.
The perimeter of square is given as = 4s where s is the side length.
Here, perimeter is 24 inches.
So, side will be:

Dividing both sides by 4;
s = 6
So, we get the side of the frame as 6 inches.
Now Monica painted 3/4 of 6 inches.
This value becomes :
and in fraction it is
This is part of 24 inches.
So, the fraction will be : 
=
= 3/16
Hence, Monica painted
of the frame blue.