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Greece Junior Math Olympiad
1990 Greece Junior Math Olympiad
3
3
Part of
1990 Greece Junior Math Olympiad
Problems
(1)
angles and diagonals in reg. 72-gon - Greece Juniors 1990 p3
Source:
9/14/2024
Let
A
1
A
2
A
3
.
.
.
A
72
A_1A_2A_3...A_{72}
A
1
A
2
A
3
...
A
72
be a regurar
72
72
72
-gon with center
O
O
O
. Calculate an extenral angle of that polygon and the angles
∠
A
45
O
A
46
\angle A_{45} OA_{46}
∠
A
45
O
A
46
,
∠
A
44
A
45
A
46
\angle A_{44} A_{45}A_{46}
∠
A
44
A
45
A
46
. How many diagonals does this polygon have?
geometry
Regular
angles