Area of a square is
For the smaller square that's
For the larger square that's
The problem indicates that the area of the small square is 1/3 the area of the large square. In other words, three times the area of the small square equals the area of the large square.

Move what's on the right to the left of the = by subtracting it from both sides.

Divide both sides by 2.

Factor by using the quadratic formula

That gives two possible answers:
The length cannot be negative so discard that.

Round it to the nearest quarter inch, so .46 rounds up to .5.

Check if .
Yes, it's close enough given we had to round up to the nearest quarter inch.

If you need help understanding math so you can solve these problems yourself, then one on one online tutoring is the answer ($30/hr). If you need faster solutions with guaranteed detailed answers, then go with personal problem solving ($3.50-$5.50 per problem). Contact me at fcabanski@hotmail.com