Greetings

1.I can understand that the universe is an indefinite structure, due to it's expansion. And i've read that scientists calculated it's exact size, more-less. Now, i've been thinking of the ways they did that and i come up with this: a single dot represented the universe begining, multiplied by the current rate of expansion, for the universe age. Now you can't use a dot, for it's a apstract thought, and you can't be really sure of how large universe was in the begining. Now it got to complicated and i wanted to ask you, how did they actualy measure the size and the age?
2.Are there any theories of what the universe shape is???