I love Google Earth and have enjoyed many Lit Trips. Now Real World Math has developed a series of math lessons using Google Earth. Search using lesson types (i.e., concept, measurement, to space and beyond!). This free site requires a password to access teacher files- while I have the password, I’ve been asked not to post it- but email me and I will share. Or there is a contact on the site. Help your students understand how math is related to real world issues.
Even if you students do not have Google Earth installed on their computers, I think this would work well as a projection.