Answer:
<em>Gardener will need 4 more plants.</em>
Step-by-step explanation:
Gardener has 780 plants and wants to plant them in an array of n rows and n columns.
The number of plants needed to do that is:
He actually has 780 plants, thus it should occur:
Taking the square root:
n=27.9
Since n needs to be an integer, we round up n to get
n=28
But , 4 more than the actual number of plants, thus:
Gardener will need 4 more plants.
Note: There are other possible results for n. If we set n=29, then and Gardener would need 841-780=61 more plants, but the question asked for the minimum number of plants.