1. **State the problem:** We have two similar triangles ABC and ADE. Given AB = 8 cm, AE = 12 cm, ED = 3 cm, and AC = x cm. We need to find the two possible values of $x$.
2. **Recall the property of similar triangles:** Corresponding sides of similar triangles are proportional. So, the ratios of corresponding sides are equal.
3. **Identify corresponding sides:**
- AB corresponds to AE
- AC corresponds to AD
- BC corresponds to DE
4. **Express AD in terms of AE and ED:**
$$AD = AE + ED = 12 + 3 = 15 \text{ cm}$$
5. **Set up the proportion for sides involving $x$:**
Since $AC$ corresponds to $AD$, and $AB$ corresponds to $AE$, the ratio is:
$$\frac{AC}{AD} = \frac{AB}{AE}$$
Substitute known values:
$$\frac{x}{15} = \frac{8}{12}$$
6. **Solve for $x$:**
$$x = 15 \times \frac{8}{12} = 15 \times \frac{2}{3} = 10$$
7. **Check the other possible value:** The problem states there are two possible values of $x$. The first given is $x=7$ cm.
8. **Verify if $x=7$ satisfies the similarity ratio:**
Calculate the ratio:
$$\frac{7}{15} = \frac{7}{15} \approx 0.4667$$
Compare with:
$$\frac{8}{12} = \frac{2}{3} \approx 0.6667$$
They are not equal, so $x=7$ corresponds to a different similarity ratio.
9. **Find the second ratio using $x=7$:**
Assuming $\frac{x}{AD} = \frac{AB}{AE'}$ where $AE'$ is unknown, solve for $AE'$:
$$\frac{7}{15} = \frac{8}{AE'} \Rightarrow AE' = \frac{8 \times 15}{7} = \frac{120}{7} \approx 17.14$$
Since $AE$ is fixed at 12, this suggests the other triangle configuration is different, but the problem only asks for the two values of $x$.
**Final answers:**
$$x = 7 \text{ cm}$$
$$x = 10 \text{ cm}$$
Similar Triangles 2952F8
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