I got u
you need the bases first.
draw the sketch. label the top base a, the bottom c.
now notice on c, it is longer than a by 2*k, where k is the length of the base below end triangles.
Pyth: (c-k)^2=25^2-15^2
or c-k=20cm
but c=a+2K
Now the median length:
median=(a+c)/2=(c-2k+c)/2
=2c-2k=2(c-k)=20cm
area=median*height=20cm*15cm
=300cm^2
