I can't figure this one out

Answer:
21
Step-by-step explanation:
Law of cosines
[tex]\tt c=\sqrt{AC^2+BC^2-2\cdot AC \cdot BC\cdot\cos C}\\\\{} \ \ =\sqrt{10^2+17^2-2\cdot10\cdot17\cdot(-0.152985)}\\\\{} \ \ \approx\sqrt{100 +289+52} \approx\sqrt{441} \approx21 \ units[/tex]
Answer:
[tex] c = 21 [/tex]
Step-by-step explanation:
You are given the lengths of two sides and the measure of the included angle. You must use the Law of Cosines.
[tex] c^2 = a^2 + b^2 - 2ab\cos C [/tex]
[tex] c^2 = 17^2 + 10^2 - 2(17)(10)\cos 98.8^\circ [/tex]
[tex] c = 21.0004 [/tex]
[tex] c = 21 [/tex]