In ΔABC, BE is a median meeting AC at E. If the centroid is G and BG = 6 cm, find the length of the whole median BE.

Difficulty: Easy

Correct Answer: 9 cm

Explanation:

Introduction / Context:The centroid G divides each median in the ratio 2:1, counted from the vertex. This invariant allows direct recovery of the total median length when one centroid segment is known.

Given Data / Assumptions:

  • BE is a median; G is the centroid.
  • BG = 6 cm (segment from vertex B to centroid).

Concept / Approach:By definition, BG : GE = 2 : 1 along median BE. Therefore BE = BG + GE = BG + (BG/2) = 3BG/2.

Step-by-Step Solution:BE = (3/2) * BG = (3/2) * 6 = 9 cm.

Verification / Alternative check:Compute GE = 3 cm; 6 + 3 = 9, matching BE.

Why Other Options Are Wrong:7, 8, 10 cm contradict the fixed 2:1 centroid division.

Common Pitfalls:Accidentally using 1:2 instead of 2:1 from the vertex.

Final Answer:9 cm

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