+56 
AB is a radius. Line CD is tangent to circle A at point B. AB = 5 ft and EC = 8 ft.
BC = ___ ft
+506 Notice that AC is equal to the sum of the radius and EC. We know that AB is the radius, and AB is 5 ft, so AC must be equal to 5 ft + 8 ft = 13 ft.
Since BC is tangent to circle A, AB is perpendicular to BC, so ABC is a right triangle.
Let BC equal x. To find BC, use the Pythagorean theorem:
\(5^2+x^2=13^2\\25+x^2=169\\x^2=144\\x=\boxed{12}\)
