Irrational numbers can not be precisely represented in decimal form because they are non-terminating, non-repeating decimals. Also they cannot be written as a fraction as well.
Answer: 
Step-by-step explanation:
1. By definition, if
when
, then:

2. Keeping this on mind, to find the value of
when
, you must apply the following proccedure:

3. Now, you must solve for
, as following:

4. Then, the result is:

If you want to find the whole, you have to start by dividing 100% by 60%, so you can multiply that quotient by 3/4 to find the whole. 100/60=10/6=5/3. That means 5/3*60%=100%, so 3/4*5/3=whole. 3/4*5/3=15/12, and simplify to get 5/4, or 1 1/4. 3/4 is 60% of 1 and 1/4, or 5/4.
Answer:
1) EA= 50 (because is a vertical angle with CB and vertical angles are congruent)
3) DEB = 210 ( to find AB subtract EA from 180, so 180-50 = 130. Then add together arcs DE, EA and AB to find the total measurement of DEB)
5) AB = 130 (I explain how to find it in question #3)
6) CDA = 180 ( To find CDA just add the measurements of CD, DE and EA together)
(sorry don't know the rest, hope this helps)
Andrea drove 50miles/hour
refer to pic for working