半径为r的圆的面积是边长为r的正方形面π倍.______.(判断对错)
设圆的半径为r,
则正方形的面积=r×r=r2,
圆的面积=πr2,
所以πr2÷r2=π倍.
故答案为:√.
— How can I reserve the tickets?
— _____ phone. [ ]
A. On
B. With
C. By
D. In
电动叉车停车时要拉紧手制动,将货叉降到最低位置关闭电销开关。