Nice 
area=pir^2
the areas are
pir^2+pi(2r)^2
they add to 8pi
8pi=pir^2+pi(2r)^2
undistribute pi
8pi=pi(r^2+(2r)^2)
divide both sides by pi
8=r^2+(2r)^2
expand
8=r^2+4r^2
add
8=5r^2
divide by 5
8/5=r^2
sqrt both sides
√(8/5)=r
double since it is double
2√(8/5) is radius of bigger aka (4√10)/5
radius=(4√10)/5
        
             
        
        
        
Answer:
Can you please give a clearer explanation of what is your question?
Step-by-step explanation:
 
        
             
        
        
        
To write down notes while you are in the class because I find it easier to explain it to yourself. You can use flashcards or study your textbook. I find the first suggestion best. 
        
                    
             
        
        
        
300 - 30 3/10 = 269 7/10
hope this helps