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Construct a pair of tangents to a circle of radius 4 cm which are inclined to each other at an angle of 60^{o}.

 

 
 
 
 
 

Answers (1)

To construct a pair of tangents to a circle of radius 4 cm which is inclined to each other at an angle of 60^{o}.

We must know that angle at the centre in double the angle between the tangents.

The angle subtended at the centre =120^{o}

Steps for construction:

(i) Draw a circle of radius 4 cm

(ii) Draw a radius BO

(iii) Draw an angle of 120^{o} from point O and let the ray interact the perimeter of the circle at point C

(iv) Now draw a 90^{o} angle from point B

(v) Draw a 90^{o} angle from point C

(vi) When we will extend the rays from point B and point C they will meet at point A

(vii) We get the required angles AC \: and \; AB with angle of 60^{o} between them.

Justification :

ABOC  is a quadrilateral hence some of the external angles should be equal to 360^{o}

\Rightarrow \angle A+\angle B+\angle O+\angle C=360^{o}

\Rightarrow \angle A+90^{o}+120^{o}+90^{o}=360^{o}

\Rightarrow \angle A+300^{o}=360^{o}

\Rightarrow \angle A=60^{o}

Hence justified the angle between tangents is 60^{o}

Posted by

Safeer PP

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