I mean, I don't know how to explain a generic way to solve this. Ask me about the specific train of thought if you are interested:
7 * 18 + 45 / 3 - 2 = 139
Step-by-step explanation:
HERE,
as,it is a right angle triangle,
x=

The formula is L = 2 pi r * (angle/360). We have what we need to figure it out. Do the work inside the () first. 72/360 = .2. So we have 2 pi (5) (.2). Do all that multiplication to get L = 2pi
1,000,000,000 . (one trillion)
welcome