Answer:
C
Step-by-step explanation:
Let's find the area of each of the two circles.
First Circle:
The first circle has a diameter of 10 inches. That means the radius is 5 inches. So, its area is:

Second Circle:
The second circle has a diameter twice that of the first. So, the diameter is 20 inches. This means that the radius is 10 inches. Find the area:

Now, find the ratio between them by dividing:

Simplify:

1/4 is the same as 1:4
So, our answer is C :)
Answer:
No it's not a function. Functions can't have the same x value.
Answer:
7. 36 8. 1 9. 21
Step-by-step explanation:
You plug in the variables in the equation.
7.
8. 
9. 
For this question, it would be most effective to use an algebraic expression to more easily show what the question is asking. If we use the variable "k" to show the distance in km that he cycled on Sunday, we know that the amount he cycled on Saturday equals k + 12, and the amount that he cycled on the weekend should be the amount of Saturday plus the amount of Sunday. If we write this as an equation we say:
k + k + 12 = 38
=> 2k + 12 = 38
Now we can just rearrange and solve for k:
=> 2k = 26
=> k = 26/2 = 13
Therefore Patrick cycled 13km on Sunday
To solve the answer, we just add 12km to the value for Sunday like so:
12 + 13 = the amount he cycled on Sunday
Hope this helped, remember to please try and understand the maths as well as the answer :))