Answer:

Step-by-step explanation:
The formula of the circumference of a circle is
.
The length of an arch can be found by using the ratio of circumference to the arc.
First, find the circumference of the circle:

Then you find the ratio:
The length of the arc is 90/360, which is 1/4, of the circumference.
Finally, find the length of the arc:
or 
I hope this helps :)
Since they're vertical angles, they're equal in degree measure
since they're equal, we can make the two expressions equal to each other
5a - 1 = 2a + 20
add 1 to both sides
5a = 2a + 21
subtract 2a from both sides
3a = 21
divide both sides by 3a
a = 7
now, plug the answer you found for a into one of the two expressions
5a - 1 becomes (5*7) - 1, which equals 34
to double check that they're equivalent (since they're vertical angles)
2a + 20 becomes (2*7) + 20, which equals 34
both angles are 34 degrees!
Answer:
r=4
Step-by-step explanation:
<span>In addition to linear, quadratic, rational, and radical functions, there are exponential functions. Exponential functions have the form f(x) = <span>bx</span>, where b > 0 and b ≠ 1. Just as in any exponential expression, b is called the base and x is called the exponent.</span>
<span>An example of an exponential function is the growth of bacteria. Some bacteria double every hour. If you start with 1 bacterium and it doubles every hour, you will have 2x bacteria after x hours. This can be written as f(x) = 2x.</span>
<span>Before you start, f(0) = 2<span>0 </span>= 1</span>
<span>After 1 hour f(1) = 21 = 2</span>
<span>In 2 hours f(2) = 22 = 4</span>
<span>In 3 hours f(3) = 23 = 8</span>
and so on.
<span>With the definition f(x) = <span>bx</span> and the restrictions that b > 0 and that b ≠ 1, the domain of an exponential function is the set of all real numbers. The range is the set of all positive real numbers. The following graph shows f(x) = 2x.</span>
<span> </span>
13 because decimal is 4 or below let it rest or 5 or more go up one more