Question

Is line AB tangent to the circle

Answer 1

no it is not a tangent

for it to be a tangent to the circle Angle A would have to be a right angle.

to check if its a right angled triangle, you can use pythagoras.

$\sqrt{ {7.5}^{2} + {16}^{2} } = 17.67059...$

this shows it is not a right angled triangle because this calculation does not give us 10.3

therefore it is not a tangent and there is no right angle