Respuesta :
A varies directly to r means that A= kr
Substitute the given value : 12 = 2(k) —> k=6
Eqn : A=6r
When r=5,A= 6(5)= 30 thus A= 30
Substitute the given value : 12 = 2(k) —> k=6
Eqn : A=6r
When r=5,A= 6(5)= 30 thus A= 30