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just for fun. let O be center of circle.tan(OCB) = 1/2thus tan(ECB) = 4/3thus cos(DCE) = cos(90 - ECB) = sin(ECB) = 4/5EC = 2 / cos(DCE) = 2 / (4/5) = 5/2
(2)^2=4 360°ABCD/4 = 90°ABCD 3^30 3^5^6 3^5^13^2 1^1^13^2 3^2 (ABCD ➖ 3ABCD+2)
just for fun. let O be center of circle.
tan(OCB) = 1/2
thus tan(ECB) = 4/3
thus cos(DCE) = cos(90 - ECB) = sin(ECB) = 4/5
EC = 2 / cos(DCE) = 2 / (4/5) = 5/2
(2)^2=4 360°ABCD/4 = 90°ABCD 3^30 3^5^6 3^5^13^2 1^1^13^2 3^2 (ABCD ➖ 3ABCD+2)