Question 954475
"Points A,B,C, and D are consecutive vertices of a regular decagon with sides 20 cm long. Ray AB and Ray DC are drawn and intersect at X. Find BX".
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Each exterior angle is 36 degrees (360/10)
CBX is an isosceles triangle with angles 36, 36 & 108 degrees.
The altitude from X to BC (Point Y) makes 2 right triangles with angles of 36, 54 & 90 degrees and BY = 1/2 of BC = 10
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cos(36) = 10/BX
BX = 10/cos(36)
BX =~ 12.36