Final Answer:
AC is equal to 68.
Step-by-step explanation:
To find AC, we need to use the information provided about the segments BC, AD, and BD. The given values are:
![\[BC = 3x - 81\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/7683ukrwai2wc0cib1vzfcnfxrendzd22t.png)
![\[AD = 6x - 30\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/xngpfsf790alh65euu1juozd0oo15mdcg1.png)
![\[AC = 11x - 290\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/n66hthyn3ywfrkoie5jdby1wyr9y04tqnw.png)
![\[BD = 115\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/lfs3pcnwk6rp3d5ht3hsg08txt3pulr5wy.png)
Firstly, we'll establish the relationship between BC and BD:
![\[BC + CD = BD\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/hd5efidmuhc4o2adp2jctaagg0xj72jcrp.png)
![\[3x - 81 + CD = 115\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/wief3j1siilbusymbhsw0la25s0ydu0534.png)
![\[CD = 196 - 3x\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/1zb4kv9mfvsu3a4olzqepq7q90npelk0ay.png)
Now, we can use the fact that AC is equal to the sum of BC and CD:
![\[AC = BC + CD\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/ox2bqopevykn7p9def7bexhd42cvnwqrl5.png)
![\[11x - 290 = 3x - 81 + 196 - 3x\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/72y51n7hr64y9ixtd5s7bvoz4jmgcfe879.png)
![\[11x - 290 = 115\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/glyg8sq1ikmhu19syh3cvma2y9ohb7ajex.png)
Solving for x:
![\[11x = 405\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/4ot6bd9dyuk11b724hjyfm05r5gh5sn86b.png)
![\[x = 37.5\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/bu535x0te071c0s2uyrbbs81t1k8nnofd2.png)
Finally, we substitute this value back into the expression for AC:
![\[AC = 11(37.5) - 290 = 68\]](https://img.qammunity.org/2024/formulas/mathematics/high-school/iwcf65klgh2pkwfja31j4ib5qdkqb71wnf.png)
Therefore, the length of AC is 68 units. The explanation demonstrates a clear step-by-step approach to solving the problem, from establishing relationships between the given segments to the final calculation of the length of AC using the determined value of x.