Hypotenuse Calculations
1. **State the problem:** Calculate the length of the hypotenuse for each right triangle, given one angle (other than the right angle) and the length of a side adjacent to the right angle.
2. **Recall SOH CAH TOA:** Since we know the angle and the adjacent side, we use the cosine ratio:
$$\cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}}$$
3. **Solve for hypotenuse:**
$$\text{hypotenuse} = \frac{\text{adjacent}}{\cos(\theta)}$$
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**(a)** $\theta=35^\circ$, adjacent = 8 cm:
$$\text{hypotenuse}_a = \frac{8}{\cos(35^\circ)}$$
Calculate:
$$\cos(35^\circ) \approx 0.8192$$
$$\text{hypotenuse}_a = \frac{8}{0.8192} \approx 9.76 \text{ cm}$$
**(b)** $\theta=70^\circ$, adjacent = 3 cm:
$$\text{hypotenuse}_b = \frac{3}{\cos(70^\circ)}$$
Calculate:
$$\cos(70^\circ) \approx 0.3420$$
$$\text{hypotenuse}_b = \frac{3}{0.3420} \approx 8.77 \text{ cm}$$
**(c)** $\theta=41^\circ$, adjacent = 18 cm:
$$\text{hypotenuse}_c = \frac{18}{\cos(41^\circ)}$$
Calculate:
$$\cos(41^\circ) \approx 0.7547$$
$$\text{hypotenuse}_c = \frac{18}{0.7547} \approx 23.84 \text{ cm}$$
**(d)** $\theta=42^\circ$, adjacent = 33 cm:
$$\text{hypotenuse}_d = \frac{33}{\cos(42^\circ)}$$
Calculate:
$$\cos(42^\circ) \approx 0.7431$$
$$\text{hypotenuse}_d = \frac{33}{0.7431} \approx 44.41 \text{ cm}$$
**Final answers (3 significant figures):**
- (a) 9.76 cm
- (b) 8.77 cm
- (c) 23.8 cm
- (d) 44.4 cm