If two tangents inclined at an angle 60° are drawn to a circle of radius 5 cm, then what is the length of each tangent?
If two tangents inclined at an angle 60° are drawn to a circle of radius 5 cm, then what is the length of each tangent?
Solution
The circle has radius 5 cm. Two tangents are drawn from an external point, with an angle of 60° between them.
Let O be the center of the circle, P be the external point where the tangents meet, and A and B be the points where the tangents touch the circle.
The line OP bisects the angle between the two tangents.
Since angle APB = 60°:
Angle OPA =
Angle OPA = 30°
Consider triangle OAP:
The tangent is perpendicular to the radius at the point of contact, so angle OAP = 90°.
OA = 5 cm (radius)
PA = length of tangent (to find)
In right triangle OAP:
cm
Therefore, the length of each tangent is cm.
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