Given:
AB || DE
BC = 14
CD = 7
CE = 7
DE = 5
To prove:
The two triangles are congruent.
Consider the two triangles ABC and EDC.
By AAA similarity, If any two angles of a triangle are equal to any two angles of another triangle, then the two triangles are similar to each other.
Therefore,
So, the corresponding sides are proportional.
So, equating (1) and (2), we get
AB = 35
So, equating (2) and (3), we get
AC = 49
Thus, the missing sides are AB=35 and AC=49.