Answer:

Step-by-step explanation:
Proportional functions can be represented by
, where
is a constant of proportionality and
represents any point the line passes through.
In the graph, we can see the line passes through (20, 40). Therefore, we can plug in these coordinates to find the constant of proportionality:

Inverse variation:

k is a constant
Use the given information (when x=4 y=4) to find the value of the constant:

Then, the given relationship has the next equation:

Use the equation above to find y when x=2:

Then, when x=2, y=8
Answer:
A = pi r^2
Step-by-step explanation:
The formula for area of a circle is given by
A = pi r^2
Answer:
300 g
Step-by-step explanation:
First divide the mass of those 12 marbles (60 g) by the number of marbles which have 60 g mass (12 marbles). You'll get the answer as 5 g , which means 5 g is the mass of 1 marble. Now multiply the answer by 60 (specification of marbles). You'll have the answer as 300 g.
i.e.
60 / 12 = 5
5 x 60 = 300