Answer:
CD = EC ⇒ proved down
Explanation:
If a point lies on a segment, then it divides the segment into two parts, the sum of their length equals the length of the segment
Example:
If point Z lies on the segment XY, then Z divides XY into segments XZ and ZY, where XY = XZ + ZY
Let us use this fact to solve the question
∵ BD and EF intersected at point C
∴ C divides BD into two segments BC and CD
∴ C divides EF into two segments EC and CF
→ By using the fact above
∴ BD = BC + CD
∴ EF = EC + CF
∵ BD = EF ⇒ given
→ Equate their right sides
∴ BC + CD = EC + CF
∵ BC = CF ⇒ given
→ That means their adding segments are equal
∴ CD = EC ⇒ proved