They're all used for differentiating types of measurement in mathematics and science.
You do 390/100 = 180/x then 390×X=390X
180×100=18000
390X=18000
390X÷390=X
18000÷390=46.15384615=46%
Bet what is it?................
The slope is the change in Y over the change in X.
Use the two blue dots on the graph :
(-1,0) ans (3,4)
Slope = (4 - 0) / (3 - -1)
= 4 / 4
= 1
This is kinda hard to explain but I'll try my best. Here's a tip, the fractions that are on the ruler really mean 10,20,30,40,50,60,70,80,90, and 100. So, when you look at the decimals on number 7, you have to try to turn them into fractions in your head. For example, 0.9 is actually 9/10 or 90.