77/5=99/x
77x=5*99
77x=495
x=495/77
x=6.4
she needs to study 6.4 hrs to get 99
        
             
        
        
        
Answer:
B. 2 in. 
Step-by-step explanation:
First, put the two perimeters together to form a fraction. 
192/48, which can simplify to 4/1
Now, following the order in which you put the perimeters (I used C/D,) set it equal to the sides. 

Now, cross multiply. (multiply 1 and 8, 4 and x.) 

Now, solve. 
x=2 inches. 
 
        
             
        
        
        
Answer:
see explanation
Step-by-step explanation:
Using the rules of exponents
• 
 ⇔ 
• 
 = 1
• 
 × 
 ⇔ 
Given
(a)
 = 
(b)
 = 3³
(c)
 × 
 × 
= 
 × 1
= 
= 