Dinosaur Mike told us that a T - rex would be HUGE! As big as a three storey building! We tried to imagine how big his arm would be ..... so we found a long tube that looked just the right shape (and size) for a dinosaur arm and compared it to ours! We measured with plastic bricks and found that a child's arm is one brick long and the tube (dinosaurs arm) is eight and a half bricks long! Have you seen it hanging in our room?