Answer:
y = 2x
Step-by-step explanation:
Given y is directly proportional to x then the equation relating them is
y = kx ← k is the constant of proportion
To find k use the condition when x = 4, y = 8, that is
8 = 4k ( divide both sides by 4 )
2 = k, thus
y = 2x ← equation of proportion
Answer:
The volume of the cone is 
Step-by-step explanation:
The given cone has a radius of 10 cm and and height of 9 cm.
The volume of a cone is given by:

We substitute r=10 and h=9 ,
to obtain:

Simplify exponents to get:

Simplify:

Therefore the volume of the cone is 
Answer: b
Step-by-step explanation: