Respuesta :

apologiabiology
first one

20cm=diameter
perimiter of this one is (pi times radius^2)divided by 2+ 20

diameter=2radius
radius=diameter times 1/2
diameter=20
20/10=radius=10

3.14 times 10^2=314
314 times 1/2=157
157+20=177 cm
perimiter=177 cm