GRE
A (a, b) + A (b, c)
A (a, c)
The radius of the circle
6
x
y
a
b
The perimeter of the regular polygon
3 times the perimeter of triangle OAB
Length of AC
Length of BE
∠ABD
∠BCD + ∠CDB
Length of AB
Length of BC
AB
BC
25000 +道题目
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