27) if a = 1/a
multiply both sides by a
a * a = 1/a * a
a^ 2 = 1
Answer is D) 1
28)
6 x 75 = 450
7 x 80  = 560
8 x 85 = 680
9 x 90 = 810 
Total all students in class = 6 + 7 + 8 + 9 = 30 students
Total score of whole class:
450 + 560 + 680 + 810 = 2500
Average = 2500 /30 = 83.3 = 83 1/3
Answer is C) 83 1/3
 
        
             
        
        
        
3 4/5 because if 5 only goes into 19 3 times and then there is 4/5 left
        
                    
             
        
        
        
Answer:
m<BGC = 145°
Step-by-step explanation:
<AGC and <DGB are vertical angles. Vertical angles are congruent. Therefore:
m<AGC = m<DGB 
 (substitution)
 (substitution)
Collect like terms
 
 
 
 
Divide both sides by -5
x = 5
m<BGC = 180 - (m<AGC) (linear pair)
m<BGC = 180 - (3x + 20)
Plug in the value of x
m<BGC = 180 - (3(5) + 20) = 180 - 35
m<BGC = 145°
 
        
             
        
        
        
You need to add up all the sides to find the perimeter.