Since interior angles of any triangle add up to 180 degrees, we have
![\angle MKH+\angle KHM+\angle KMH=180](https://img.qammunity.org/2023/formulas/mathematics/high-school/d3us4qjqhnk5zoei3za7rihdumrtdb2hl9.png)
Now, by substituting the given values, we get
![90+51.6+\angle KMH=180](https://img.qammunity.org/2023/formulas/mathematics/high-school/xp8xo474lt58aong7v9lq2hpsdysz6rf2t.png)
which gives
![141.6+\angle KMH=180](https://img.qammunity.org/2023/formulas/mathematics/high-school/v4xtj33c6qi58rqibnqsvhilpn28xk3ypr.png)
Then, by subtracting 141.6 to both sides, we have
![\angle KMH=38.4](https://img.qammunity.org/2023/formulas/mathematics/high-school/7dmj423x3jk8yba1exl1xw67twcwp67ju0.png)
Then, by comparing with the given options, the answer is the last option.