Air Distance Question.?

Question

(I got this out of my geometry book)

The air distance between Jacksonville, Florida and Merritt Island, Florida is 148 miles and the air distance between Merritt Island and Fort Pierce, Florida is 70 miles. Given that the air distance between Jacksonville and Fort Pierce is 218 miles, does Merritt Island fall on the line connecting Jacksonville and Fort Pierce?

P.S. Along with the answer, can i also have some explanation as to why the answer is correct.

Thanks!

Answer 1

Jacksonville to Fort Pierce is 215 miles.

Jacksonville to Merritt Island is 152 miles.

Merritt Island to Fort Pierce is 63 miles.

Merritt Island is on the great circle route between Jacksonville and Fort Pierce.

Answer 2

Yes. Because 148+70=218, it Merritt Island would have to fall on the line connecting Jacksonville and Fort Pierce.