What is the greatest common factor of 30 and 15

In the coordinate plan (-6,9) b (3,9) c (3,3) def is shown in the coordinate plan below

You are assembling pieces of an iron gate to complete a fence. the finished gate will look like the one below. in order to assemble the gate it is important to under how the pieces are related. part 1: how are pies 1 and 2 in the archway related? part 2: how are the rectangular sections 5 and 6 in the center of the gate related to each other?

Which number line correctly shows 0.8 + 0.3?