学习了圆的面积计算公式后,如果题中已知圆的周长求面积,很多同学都会按部就班地先利用圆的周长求出半径,再将半径代入圆的面积计算公式中求面积。这种方法是可以的,但是如果同学们能够把圆的相关知识联系起来,就会得到更简便的求面积的方法。 After learning the calculation formula of the area of ​​a circle, if the area of ​​the circumference of the circle is known, a lot of students will use the circumference of the circle to find the radius first and then substitute the radius into the area of ​​the circle to find the area. This method is acceptable, but if students can relate the relevant knowledge of the circle, they will find it easier to find their own way.