Answer:
AB = 19.6 cm
Step-by-step explanation:
Let AB be represented by c. Applying the cosine rule, we have;
[tex]c^{2}[/tex] = [tex]a ^{2}[/tex] + [tex]b^{2}[/tex] - 2ab Cos C
= [tex]12^{2}[/tex] + [tex]18^{2}[/tex] - 2(12 x 18) Cos [tex]79^{o}[/tex]
= 144 + 324 -432(0.19081)
= 468 - 82.4299
[tex]c^{2}[/tex] = 385.5701
c = [tex]\sqrt{385.5701}[/tex]
c = 19.6359
The side AB of the given triangle is 19.6 centimetres.
