Rewrite the text in latex code format, always expressing mathematical expressions in the text using inline LaTeX math mode, enclosed in single dollar signs. For example: $E = mc^2$. Do not use \\(...\\) or other delimiters.": Example 13.12 In triangle

Here is the rewritten text in LaTeX code format: ```latex \textbf{Example 13.12} In triangle $ABC$, $b = 4.2 \text{ cm}$, $c = 7.5 \text{ cm}$, and $A = 48^\circ 36'$, solve the triangle completely. First, sketch the triangle using the given information. Using the cosine rule: $48^\circ 36' = 48 + \frac{36}{60} = 48.6^\circ$ (Taking into account that $1^\circ = 60'$) That is, $a^2 = b^2 + c^2 - 2bc \cos A = 4.2^2 + 7.5^2 - 2 \times 4.2 \times 7.5 \cos 48.6^\circ = 17.64 + 56.25 - 63 \times 0.6613$ ```