Do number one please and make sure to show your work thank you

Answer:
24.9
Step-by-step explanation:
Law of cosines is : [tex]a^2 = b^2 + c^2 - 2bc(cos(A))[/tex]
Plug in 23 and 15 for b and c, and 23 for A
[tex]a^2 = 23^2 +15^2 - 2(23*15)(cos(23))[/tex]
Simplify
[tex]a^2 = 254 -690cos(23)[/tex]
Simplify
[tex]a= \sqrt{254 -690cos(23)\}[/tex]
Solve
approx . 24.9