Answer:
2x+4
Step-by-step explanation:
remember the formula (a+b)^2=a^2+b^2+2ab
in this case, 4x^2 would be a^2, 16 would be b^2, and 16x would be 2ab
so, the variable a would be 2x and the variable b would be 4
so, you can turn 4x^2+16x+16 into (2x+4)^2
and since the area of a square is (one of its sides)^2, or in this case (2x+4)^2, the length of one side of the lawn will be 2x+4
problems where you have to use the (a+b)^2=a^2+b^2+2ab formula to turn trinomials into binomials squared are very common, so make sure to look out for questions like these and be ready to use this formula
