【Haichuan Teahouse】Brain-teasing Series: You can figure it out at a glance; if not, it’s tough enough to make you hit your head
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As shown in the figure, it is composed of a trapezoid and a rectangle; find the area of the shaded part. For those who can do it, the answer is obvious at a glance; for those who can’t, it’s difficult and makes one scratch their head. Everyone, please share your methods.
This post was last edited by Yang Qing on 2022-7-28 at 11:36. Let’s think about it first; it seems there might be a solution
If the height of the trapezoid approaches zero infinitely, then the area of the shadow approaches half the area of the rectangle. But it’s tricky to prove whether the shadow remains a constant regardless of how the trapezoid changes; let’s see how experts go about proving it.
This post was last edited by Yang Qing on 2022-7-28 at 12:11; algebraic expressions are still needed, right?
CFG=CEG; Shadow area=CED=8*10/2=40