Equilateral triangles have three equal angles, so we right away know that x=60º. Then, we just solve (3(60)-70)º, which is 110º, for the answer.
 
        
                    
             
        
        
        
Answer:
3.1
4.2
5.2
42
Step-by-step explanation: Just copy the other cone and find half of the diameter to find the radius the cones are congruent.
 
        
                    
             
        
        
        
Answer:
25
Step-by-step explanation:
<ABD=<BDC
Check it out 
 
        
                    
             
        
        
        
N4=c
n times 4, n being a number of notebooks, would equal c, or the overall cost.