the triangles look like they are identical, just different in size only. Since DE= 15 and AB=10 that may mean that they have a 5cm difference making side BC= 7cm since EF= 12 minus 5 equals 7cm. Now for the other angles, a triangle no matter what,if we put all their angles together equal 180°. We already know angle A= 20 so the same applies to angle D. We also know that angle F=65 degrees, that makes angle C the same. The only thing that's left are angles B and E that can be found by adding our other angles. So if A+C(20+65)=85 then 180-85=95 degrees is angle B and since the triangles are identical the same goes to E.
