aiii) How long does it take for the airplane to reach A?

*Got this one, too.*
At A the airplane changes direction so it now flies towards B. The angle between the original direction and the new direction is theta as shown in a second diagram. This diagram also shows the point Y, between A and B, where the airplane comes closest to X.

b) Use the scalar product of two vectors to find the value of theta in degrees.

*I'm guessing that I should use the vectors ***OA** and **AB **but I don't know how I'd actually carry that out.
ci) Write down the vector

**AX**.

*???*
cii) Show that the vector

**n **= <-3, 4> is perpendicular to

**AB**.

*I think I know how to do this one.*
cii) Calculate the distance XY.

*???*
d) How far is the airplane from A when it reaches Y?

*I guess I need to know some of the previous answers to get this one!*