Step by step
The question
Question: change 3 yd² to square inches.
1 Change the length
This square is 1 yard on each side.
Its area is 1 square yard.
1 yard is 36 inches.
So each side is 36 inches long.
2 Change the area
So the square holds 36 rows of 36 small squares, each 1 square inch.
We draw only a few of them.
So 1 square yard is 36 inches times 36 inches.
36 times 36 is 1,296.
So 1 yd² = 1,296 in².
Not 36: the 36 comes in twice.
3 Multiply
Each square yard is 1,296 square inches.
We have 3 of them, so we multiply: big unit to small unit.
Careful!
Times 36 only changes a length.
A square has two sides to change: times 36, and times 36 again.
3 times 1,296 is 3,888.
So 3 yd² = 3,888 in².
4 Check
Let's check: go back the other way.
Divide by 1,296.
We get 3 square yards again.
So it is right!
Let's look back.
First: change the length.
Then: change the area.
Then: multiply.
Last: check.