Plz help me with this taks test q? its a past one just for study for the one i have to take to get in school?

So the diameter is 16cm and we need to figure out circular bottom edge of the lamp which is actually the cirference. So we knew that that the equation of the cirference is the 2 *pi *r. The r in the equation stands for radius which is HALF the diameter. So we have all the parts, lets plug into the equation. So r is 8 because 16/2=8. 2*pi*8 which is 50.24 which about 50cm! (For pi I used 3.14)