【Haichuan Teahouse】Brain Series: Always confused between circles and squares
Thread Content
The question is as shown in the picture. The side length of the square is 4. Find the area of the circle.
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untie: As shown in the figure, draw a large triangle, and the circle is the circumcircle of the large triangle. (The mid-perpendicular from the circumscribed circle to the side is a right angle) It can be proved that the two shaded triangles are similar. According to the median line theorem, the value marked 1.000 above is 1, and then the value marked 0.5000 on the right can be found. Then the direct value of this circle is 5, and it is OK to know the diameter and area.
Using the principle of similar triangles, the radius is 2.5
The [Ocean Equipment Guess] series will continue to be updated in 2021, and all Haichuan friends are welcome to actively participate! https://bbs.hcbbs.com/thread-2079686-1-1.html (Source: Haichuan Chemical Forum - Huahaichuanliu) ------------------------------------------------------------------------------- [Ocean Safety Everyone Talks] series of summary posts, which are being continuously updated. Everyone is welcome to participate in the exchange! https://bbs.hcbbs.com/thread-3235104-1-1.html (Source: Haichuan Chemical Forum-Haichuanliu)
You can also directly construct a large triangle to find the diameter,