问题
填空题
两个圆半径比是3:2,周长比是______,面积比是______.
答案
设大圆的半径为3a,则小圆的半径为2a,
则:(2π×3a):(2π×2a),
=6πa:4πa,
=(6πa÷2πa):(4πa÷2πa),
=3:2,
[π(3a)2]:[π(2a)2],
=9a2π:4a2π,
=(9a2π÷a2π):4a2π÷a2π),
=9:4;
故答案为:3:2,9:4.
两个圆半径比是3:2,周长比是______,面积比是______.
设大圆的半径为3a,则小圆的半径为2a,
则:(2π×3a):(2π×2a),
=6πa:4πa,
=(6πa÷2πa):(4πa÷2πa),
=3:2,
[π(3a)2]:[π(2a)2],
=9a2π:4a2π,
=(9a2π÷a2π):4a2π÷a2π),
=9:4;
故答案为:3:2,9:4.