Answer: 224 cm.

Instructions. There are five pairs of segments that sum up to AG and AG itself. There are three pairs of segments that sum up to BF and BF itself. There is one pair of segments that sum up to CE and CE itself. Therefore, the total length of all segments is $6 \cdot 23 + 4 \cdot 17 + 2 \cdot 9 = 138 + 68 + 18 = 224($ cm $)$.

Criteria. Correct answer without justification: 2 points.

For a computational error with correct justification, 3 points are deducted.
3. On a line, seven points A, B, C, D, E, F, G are marked in the given order. It turned out that $A G=23 \mathrm{~cm}, B F=17 \mathrm{~cm}$ and $\mathrm{CE}=9 \mathrm{~cm}$. Find the sum of the lengths of all segments with endpoints at these points.