If you are trying to name them the first and 2nd one are cones, the third is a triangular pyramid and I believe the last one is called a square pyramid
7.538 start from 8 which is in the thousandth place. 8 will make the 3 turn into 4. 4 is too low so it doesn't change the 5. the 5 change the 7 to 8. so anything that is 5 and up you round up
