Answer:
The base of the rectangle is 21 mm.
Explanation:
Given that a rectangle's area is 336 mm, and its height is 16 mm, to determine what is the measure of its base, the following calculation must be performed, knowing that the area of a rectangle arises from multiplying its base by its height:
16 x X = 336
X = 336/16
X = 21
Therefore, the base of the rectangle is 21 mm.