A circular window has a diameter of 40 centimeters. What is the circumference of the window? Use 3.14 for pi.

A.
62.8 cm

B.
125.6 cm

C.
251.2 cm

D.
502.4 cm

Question

A circular window has a diameter of 40 centimeters. What is the circumference of the window? Use 3.14 for pi. 

  
 
 
 A.   
    62.8 cm    
  
 
 
 B.   
    125.6 cm    
  
 
 
 C.   
    251.2 cm    
  
 
 
 D.   
    502.4 cm

bahrom7893 · Answer

$$C=2*\pi*r=2*3.14*\frac{d}{2}=2*3.14*\frac{40}{2}=2*3.14*20$$

anonymous · Answer

can you explain

bahrom7893 · Answer

That's just the formula, and radius is always half of the diameter

goldphenoix · Answer

Alright. To find the circumference, you want to use the formula: $$\large \large D *3.14 = C$$ Where D is the diameter. 
So what do you think you have to do?

anonymous · Answer

multiply 20 by 3.14 to get 62.8

goldphenoix · Answer

Isn't the diameter 40?

anonymous · Answer

oh yes sorry so it would be multiply 40 by 3.14 to get 125.6

goldphenoix · Answer

Correct!

anonymous · Answer

thankyou for your help