Circles

1003021508

Level: 
A
A triangle is inscribed in a circle. Its vertices divide the circle into three arcs whose lengths are in the ratio 2:4:9. Determine the measures of the interior angles of the triangle.
24; 48; 108
30; 40; 110
48; 15; 117
15; 60; 105

1103021509

Level: 
A
A regular dodecagon ABCDEFGHIJKL is inscribed in a circle. Find the measures of all interior angles of the quadrilateral ABHJ. (See the picture.)
α=120; β=75; γ=60; δ=105
α=105; β=60; γ=75; δ=120
α=120; β=30; γ=60; δ=105
α=105; β=75; γ=75; δ=105

1103021510

Level: 
A
A regular nonagon ABCDEFGHI is inscribed in a circle. Calculate the measures of all interior angles of the quadrilateral ABEH. (See the picture.)
α=120; β=100; γ=60; δ=80
α=100; β=120; γ=60; δ=80
α=100; β=100; γ=80; δ=60
α=110; β=130; γ=70; δ=50