神马作文网What if an archeologist found three
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What if an archeologist found three bones in Cairo, Egypt buried 4 meters, 7 meters, and 9 meters apart (to form a triangle)? The likelihood that more bones are in this area is very high. The archeologist wants to dig in an appropriate circle around these bones. If these bones are on the edge of the digging circle, where is the center of the circle? Can you determine how far apart each bone is from the center of the circle? What is this length?
没有问题啊,如果问半径就正余弦定理吧
再问： 能不能给一下部分过程,还有辅助线.谢谢
再答： 取最长边为a 余弦定理：cosA=(b*b+c*c-a*a)/2bc(=-2/7) 然后sinA^2+cosA^2=1，so sinA=七分之三倍根号五 正弦定理：a/sinA（=b/sinB=c/sinC）=2R，故R=10.5*根号五
再问： 能不能给一下部分过程,还有辅助线.谢谢
再答： 取最长边为a 余弦定理：cosA=(b*b+c*c-a*a)/2bc(=-2/7) 然后sinA^2+cosA^2=1，so sinA=七分之三倍根号五 正弦定理：a/sinA（=b/sinB=c/sinC）=2R，故R=10.5*根号五