In the given figure, $QR$ is a common tangent to the two given circles touching externally at $A$. The tangent at $A$ meets $QR$ at $P$. If $AP = 4.2$ cm, then the length of $QR$ is:

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Question

In the given figure, $QR$ is a common tangent to the two given circles touching externally at $A$. The tangent at $A$ meets $QR$ at $P$. If $AP = 4.2$ cm, then the length of $QR$ is:

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Accepted Answer

Step 1: $PQ = PA = 4.2$ cm and $PR = PA = 4.2$ cm (tangents from external point $P$). $QR = PQ + PR = 8.4$ cm

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