Respuesta :

calculista
let
a1=10 cm
a2=17 cm
a3=24 cm
a4=?

we know that
a2-a1=17-10-----> 7 cm
a3-a2=24-17----> 7 cm
a(n)=a1+(n-1)*7

find a4
for n=4
a(4)=a1+(4-1)*7------> a(4)=10+3*7-----> a(4)=31 cm

the answer is
31 cm