A

2010012808

Level: 
A
A regular nonagon ABCDEFGHI is inscribed in a circle. Calculate the measures of all interior angles of the quadrilateral BDGI. (See the picture.)
α=100; β=80; γ=80; δ=100
α=110; β=80; γ=80; δ=90
α=110; β=70; γ=70; δ=110
α=120; β=80; γ=80; δ=120

2010012807

Level: 
A
A regular dodecagon ABCDEFGHIJKL is inscribed in a circle. Find the measures of all interior angles of the quadrilateral BFIL. (See the picture.)
α=90; β=75; γ=90; δ=105
α=90; β=60; γ=80; δ=130
α=80; β=75; γ=90; δ=115
α=90; β=105; γ=90; δ=105