Answer is: Radius = 8.6 cm
Well, both sides are equal to 1, so I'm thinking "="
When a tangent (top line with the arrow) and a secant (other line) intersect, they form an angle (55°) equal to:
55° = ½ (the larger intercepted arc minus<span> the smaller intercepted arc)
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<span>55° = ½ (170° -x°)
55° = 85° -</span><span>½ x
</span><span>½ x = 30°
x = 60°
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