Can segment lengths of 3cm, 4cm, and 6cm be used to form a triangle?

What is the measure of ac? 5 units 13 units 26 units 39 units

Consider the diagram. which line segment has the same measure as st? rx tx sr xs

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