Answer:
[tex]\huge\boxed{c\approx15.5ft}[/tex]
Step-by-step explanation:
Use the cosine law:
[tex]c^2=15^2+20^2-2(15)(20)\cos50^o\\\\(\cos50^o\approx0.6428)-\text{look at the picture}\\\\c^2=225+400-600(0.6428)\\\\c^2=625-385.68\\\\c^2=239.32\to c=\sqrt{239.32}\\\\c\approx15.46997\to c\approx15.5[/tex]
