Contact us
Choose a category below so we can get back to you as quickly as possible.
設大圓的半徑為R,小圓的半徑為r;根據題意可得:R2-r2=20(平方分米),所以圓環的面積是:3.14×20=62.8(平方分米);答:這個圓環的面積是62.8平方分米.
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.