Answer: 2sqrt(10)
Step-by-step explanation:
I'll do the top left one as an example, you can do the rest.
From the geometric mean theorem, we get that 5/x = x/8.
This rearranges to x^2 = 40
x = 40 = 2sqrt(10)
The original 15 people are 10% of the total number of people who received the mail.
Step-by-step explanation:
Given,
Number of people who received mail = 15
Mail further sent to 3 more friends;
Number of people who received mail from 15 people = 15*3 = 45 people
Number of people who received mail from 45 people = 45*2 = 90 people
Total number of people = 15+45+90 = 150 people
Now,
Percent of original people = 
Percent of original people = 
The original 15 people are 10% of the total number of people who received the mail.
Keywords: multiplication, percentage
Learn more about percentages at:
#LearnwithBrainly
Answer:
The next mark should be at (3,-3)