7/10 / 3/1
7/10 x 1/3
7/30
(not sure if this is correct)
Answer: 
Step-by-step explanation:
To solve for b, we want to use the Pythagorean Theorem as given.
b and 7 are the legs, and 12 is the hypotenuse.
[exponent]
[subtract both sides by 49]
[square root both sides]

Now we know
.
Find unit rate of pages read per minute:
(5/8)/(2/3)
(5/8)*(3/2)
(5*3)/(8*2)
(15)/(16)
15/16
Kenny reads 15/16 pages every minute (unit rate)
It is C: Given, Reflexive Property