8 and 12 are separated by 1 line, and they have a difference of 4 units, so..
count every two lines and add 4 units
this means that the blue dot is 20
EF = 50 in.
In similar figures, corresponding sides are proportional. We use the similarity statement ABCD~EFGH to write a proportion:

Cross multiply the proportion:
45*x = 75*30
45x = 2250
Divide both sides by 45:
45x/45 = 2250/45
x = 50
Answer:
13 textbook can buy.
Step-by-step explanation:
13 textbook can buy.
Disagree, the fractions are unequal and 10/15=66% while 15/20=75%
There isn't really a formula for higher numbers. you can use a calculator with the square root function