思考总结 · 步骤 1
已掌握[object Object]
[发现] 播放公式动画,观察圆面积公式是怎样从模型中来的。
步骤 1
当前步骤[发现] 播放公式动画,观察圆面积公式是怎样从模型中来的。
Formula Animation
Watch the circle become a parallelogram — that’s the picture behind A = πr².
Slice & Rearrange
More slices → the pieces line up into a near-perfect parallelogram (base ≈ πr, height = r).
Cut the circle into 4 equal wedges and lay them in a row, alternating up and down.