This is a harder construction because copying the included angle must be constructed before the second side.

The construction begins as with SSS, copy one side onto a given line.

The next step is to copy an angle, choose either end of the line segment. To copy an angle, first mark both the original and the given with the same size arc. Now measure the opening between the points of intersection on triangle ABC, using that distance mark the intersection on the copied arc. The line that goes through A' and this intersection forms an angle congruent to angle A.

We now have side A'B' copied, and angle A', therefore, we only need the length of line A'C'. We do this by measuring AC with an arc and copying that arc from A'. That only leaves drawing a segment from this point C' to B'.

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