Answer:
6 millimeters
Step-by-step explanation:
A = L × W
A ÷ L = W
42 ÷ 7 = 6
Euclidean geometry is all about shapes, lines, and angles and how they interact with each other. There is a lot of work that must be done in the beginning to learn the language of geometry. Once you have learned the basic postulates and the properties of all the shapes and lines, you can begin to use this information to solve geometry problems. Unfortunately, geometry takes time, but if you put in the effort, you can understand it.
A function
is periodic if there is some constant
such that
for all
in the domain of
. Then
is the "period" of
.
Example:
If
, then we have
, and so
is periodic with period
.
It gets a bit more complicated for a function like yours. We're looking for
such that
Expanding on the left, you have
and
It follows that the following must be satisfied:
The first two equations are satisfied whenever
, or more generally, when
and
(i.e. any multiple of 4).
The second two are satisfied whenever
, and more generally when
with
(any multiple of 10/7).
It then follows that all four equations will be satisfied whenever the two sets above intersect. This happens when
is any common multiple of 4 and 10/7. The least positive one would be 20, which means the period for your function is 20.
Let's verify:
More generally, it can be shown that
is periodic with period
.