Question

The radius of circle O is 18, and OC = 13. Find AB. Round to the nearest tenth, if necessary.

Answer 1

\[\huge BC^2 = OB^2 - OC^2 =18^2 - 13^2 \]
\[\huge BC^2 = 18^2 - 13^2 =324 -169=155 \]
\[\huge BC = \sqrt {155}\]
Since AB = 2BC = \[2 \sqrt{155} = 2 \times 12.449 = 24.898 \approx 25\]

@highschoolmom2010