To add \( \sqrt{28} + \sqrt{28} + \sqrt{28} \), we first recognize that this simplifies to:
\[ 3 \sqrt{28} \]
Next, we should simplify \( \sqrt{28} \). We can factor \( 28 \) as follows:
\[ \sqrt{28} = \sqrt{4 \times 7} = \sqrt{4} \times \sqrt{7} = 2 \sqrt{7} \]
Therefore, we have:
\[ 3 \sqrt{28} = 3 \times 2 \sqrt{7} = 6 \sqrt{7} \]
Now, let's check the provided options for match:
- \( \sqrt{58} \)
- \( 5 \sqrt{8} \)
- \( 4 \sqrt{8} + \sqrt{28} \)
- \( 5 \sqrt{44} \)
- \( 4 \sqrt{16} + \sqrt{28} \)
None of these options equal \( 6 \sqrt{7} \), but if we analyze option 3:
\[ 4 \sqrt{8} + \sqrt{28} = 4 (2 \sqrt{2}) + 2 \sqrt{7} = 8 \sqrt{2} + 2 \sqrt{7} \]
This also does not match.
Therefore, it seems that none of these options directly corresponds to \( 6 \sqrt{7} \). The correct conclusion is that \( \sqrt{28} + \sqrt{28} + \sqrt{28} = 6 \sqrt{7} \), but none of the options provided matches this result.