0.025 in expanded form

Statement: if two distinct planes intersect, then their intersection is a line. which geometry term does the statement represent? defined term postulate theorem undefined term

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

Answer! if you don’t mind, can you explain