Angle Mln
1. **State the problem:** We need to find the angle $\angle MLN$ in triangle $MLN$ where $ML=20$ cm, $MN=15$ cm, and $\angle M=62^\circ$.
2. **Identify known values:**
- Side $ML = 20$ cm
- Side $MN = 15$ cm
- Angle $\angle M = 62^\circ$
3. **Use the Law of Sines:**
The Law of Sines states:
$$\frac{\sin \angle MLN}{MN} = \frac{\sin \angle M}{LN} = \frac{\sin \angle LNM}{ML}$$
We want to find $\angle MLN$, so we use:
$$\frac{\sin \angle MLN}{MN} = \frac{\sin \angle M}{LN}$$
But we do not know $LN$ or $\angle LNM$ yet. Instead, use the Law of Cosines to find $LN$ first.
4. **Find side $LN$ using Law of Cosines:**
$$LN^2 = ML^2 + MN^2 - 2 \times ML \times MN \times \cos \angle M$$
$$LN^2 = 20^2 + 15^2 - 2 \times 20 \times 15 \times \cos 62^\circ$$
Calculate:
$$LN^2 = 400 + 225 - 600 \times \cos 62^\circ$$
$$\cos 62^\circ \approx 0.4695$$
$$LN^2 = 625 - 600 \times 0.4695 = 625 - 281.7 = 343.3$$
$$LN = \sqrt{343.3} \approx 18.52 \text{ cm}$$
5. **Use Law of Sines to find $\angle MLN$:**
$$\frac{\sin \angle MLN}{MN} = \frac{\sin \angle M}{LN}$$
$$\sin \angle MLN = \frac{MN}{LN} \times \sin \angle M = \frac{15}{18.52} \times \sin 62^\circ$$
Calculate:
$$\sin 62^\circ \approx 0.8829$$
$$\sin \angle MLN = 0.810 \times 0.8829 = 0.715$$
6. **Find $\angle MLN$:**
$$\angle MLN = \sin^{-1}(0.715) \approx 45.6^\circ$$
**Final answer:**
$$\boxed{\angle MLN \approx 45.6^\circ}$$