last thing i promise ok the length of the wing of a model airplane is 3 in. if th escale of the model to the actual plane is 1in=25ft wha tis the length of the actual wing? is it 8.3 or 0.12

Neither of those.

Think about it if the model wing is 3 inches long, the actual wing must be much longer than 25 feet.

Try again.

is it 0.12 can u help me

Use this proportion:

1/25 = 3/x

so its 0.12 right can you u just go thorough it with steps

No.

Cross multiply and solve for x.

http://www.purplemath.com/modules/ratio4.htm

so is it 75

Yay! You've got it! :-)