Answer:
Circumference = πd
where d = diameter
Step-by-step explanation:
When using this formula you don't need to multiply by 2 like you do when using the radius because the diameter is twice the radius of a circle.
Answer:
x + y = 100
5x + 2y = 35
Step-by-step explanation:
Answer:
The correct answer would be 
Step-by-step explanation:
given
we want to solve for a
How?
We can do this by using basic algebra ( isolating the variable (a ))
Step 1 subtract
from each side

now we have 
step 2 take the square root of each side

we're left with
Hence your answer is A