Iam totally lost no idea what to do

You are right.

First of all, look at the fraction bars. They have a same total length.
Then, look at the colored portion of the faction bars. They also have a same length.

You can thus tell that the two fraction bars are equal/equivalent.

So, with this in mind, we need a set of fractions that are equal to each other.

has a greatest common factor (GCF) of 2 we can reduce by, so dividing by 2 on the numerator and denominator leaves us with .
has a greatest common factor (GCF) of 3 we can reduce by, so diving by 3 on the numerator and denominator leaves us with .

Both sides are equal -- fraction bars are equal -- A is the answer.

However, that all lot is quite advanced right now! Keep this page bookmarked; when you move on to more advanced stuff, this example will come handy.

The equal sign (=) ensures that both sides, the left and right, have same values, or are equivalent.

All other signs, such as < and >, denote something else, such as greater than or equal to. This fraction bar doesn't show that, but shows equal, so we want =.

Thus, also A.

Yes i could be the length of the triangle