Answer: C
Step-by-step explanation:
Pythagorean's Theorem can only be used for right triangles. For the triangle above, the Law of Cosines must be used. The Law of Cosines can be used when you're given two sides and an angle. The general formula is below:
[tex]x^2=a^2+b^2-2abcos(theta)[/tex]
For the triangle above:
a = 23
b = 20
∅ = 47°
Therefore:
[tex]x=\sqrt{23^2+20^2-2*23*20*cos(47)} =\sqrt{529+400-920cos(47)}=\sqrt{929-920cos(47)} =17.37[/tex]
