Answer:
A. 11
Explanation:
Hi there!
We're given the trapezoid EBFD, with bases (the parallel sides) EB and DF, which equal 9 and 13 respectively
AC is a segment that belongs to EBFD, and has the measure of x
AC is a midsegment, which is a segment that connects the midpoints of 2 sides
the midpoint divides a segment to create create two congruent segments
In this example, point A is a midpoint, as it divides ED into the congruent segments EA and AD (you can tell they are congruent by their markings)
C is also a midpoint, as it divides BF into the congruent segments BC and CF
line segment AC connects the points A and C together
anyway, the measure of a midsegment in a trapezoid is the average of the bases
in other words, the midsegment (AC, or x) is equal to (EB+DF)/2
since we know the measures of EB and DF, we can substitute them into the expression above to find x
x=(EB+DF)/2
x=(9+13)/2
add the numbers on the numerator
x=22/2
divide
x=11
So the answer is A
Hope this helps! :)