There are 12 months in a yr so 12/3=4 then 1/3x4=4/3 so 1ft and 1/3 erode each yr. C is the correct answer<span />
Answer:
13
Step-by-step explanation:
The formula for cirmference is
C= π2 * r
we're using 3.14 as pi and r = radius.
the radius is always half of the diameter.
So in this case since the diamter is 4, the radius is 2. let's substitute these numbers.
C= 3.14 *2*2 and there your answer is 12.56 which rounded to the nearest tenth is 13.
Hope this helps :)
Answer:

Step-by-step explanation:
Product of of 3 and b is 3b
At least means greater than or equal too.

This is a classic example of a 45-45-90 triangle: it's a right triangle (one angle of 90) & two other sides of the same length, which means two angles of the same length (and 45 is the only number that will work). With a 45-45-90 triangle, the lengths of the legs are easy to determine:
45-45-90
1-1-sqrt2
Where the hypotenuse corresponds to sqrt2.
Now, your hypotenuse is 10.
To figure out what each leg is, divide 10/sqrt2 (because sqrt2/sqrt2 = 1, which is a leg length in the explanation above).
Problem: you can't divide by radicals. So, we'll have to rationalize the denominator:
(10•sqrt2)/(sqrt2•sqrt2)
This can be rewritten:
10sqrt2/sqrt(2•2)
=10sqrt2/sqrt4
=10sqrt2/2
=5sqrt2
Hope this helps!!