1. **Problem Statement:** Calculate the angle $\angle LQR$ in triangle $LQR$ where sides are given as $LQ=21.22$ m, $QR=19.63$ m, and $LR=1.83$ m.
2. **Formula Used:** To find an angle in a triangle when all three sides are known, use the Law of Cosines:
$$\cos(\theta) = \frac{a^2 + b^2 - c^2}{2ab}$$
where $\theta$ is the angle opposite side $c$, and $a$, $b$ are the other two sides.
3. **Identify Sides:** Here, $\angle LQR$ is at vertex $Q$, so the side opposite this angle is $LR = 1.83$ m.
Sides adjacent to $\angle LQR$ are $LQ = 21.22$ m and $QR = 19.63$ m.
4. **Apply Law of Cosines:**
$$\cos(\angle LQR) = \frac{LQ^2 + QR^2 - LR^2}{2 \times LQ \times QR}$$
Substitute values:
$$= \frac{21.22^2 + 19.63^2 - 1.83^2}{2 \times 21.22 \times 19.63}$$
5. **Calculate Numerator:**
$$21.22^2 = 450.2484$$
$$19.63^2 = 385.6969$$
$$1.83^2 = 3.3489$$
So numerator:
$$450.2484 + 385.6969 - 3.3489 = 832.5964$$
6. **Calculate Denominator:**
$$2 \times 21.22 \times 19.63 = 2 \times 416.6466 = 833.2932$$
7. **Calculate Cosine:**
$$\cos(\angle LQR) = \frac{832.5964}{833.2932}$$
Use cancellation to simplify:
$$\cos(\angle LQR) = \frac{\cancel{832.5964}}{\cancel{833.2932}} \approx 0.99915$$
8. **Find Angle:**
$$\angle LQR = \cos^{-1}(0.99915)$$
Using a calculator:
$$\angle LQR \approx 2.5^\circ$$
9. **Final Answer:** Rounded to the nearest degree,
$$\boxed{3^\circ}$$
Angle Lqr 912A36
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