6) If two angles of a triangle are 48^{o} and 72^{o}, what is the value of the third angle ?

The total angle of a triangle = 180^{o}

Therefore the sum of the other two angles must be subtracted from 180^{o}

= 180^{o} - (48^{o }+ 72^{o})

180^{o} - 120^{o}

= 60^{o}