You can use the similarity approach of these two triangles CBD and CAE
as a result:

so:
? = 6x^2 / 10 = 0.6 x^2
and the fact of:
"The segment connecting the midpoints of two sides of a triangle is parallel to the third side and equals its half length"
so:BD = 0.5 AE 10 = 0.5 * 2x >>> x= 10
Back to:
? =0.6 x^2 = 0.6 * 10^2 = 0.6 * 100 = 60
AHope that helps