The 円周 of a circle is 21pi cm. What is the area, in square centimeters? Express your answer in terms of pipi.

解

T h e c i rc u m f ere n ce o f a c i rc l e i s 21 π c m . Wha t i s t h e a re a, in s q u a re ce n t im e t ers ? E x p ress yo u r an s w er in t er m s o f p iπ .

a re a : 346.36 c m^{2}

解答ステップ

Given:

c i rc u m f ere n ce : 21 π c m

指定された円の半径

C i rc u m f ere n ce = 21 π : r = 10.5

指定された円の面積

r = 10.5 : A = 346.36059 \dots

a re a : 346.36 c m^{2}