Solution: The diameter of the semicircular drum is 12 meters, so the radius is half the diameter. Thus, $ r = \frac122 = 6 $ meters. The radius is $ \boxed6 $ meters.Question: Find $ x $ such that the vectors $ \beginpmatrix x \\ 3 \endpmatrix $ and $ \beginpmatrix 2 \\ -x \endpmatrix $ are orthogonal. - Nelissen Grade advocaten