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A and B are centres of two circles of radii 11 cm and 6 cm, respectively. PQ is a direct common tangent to the circles. If AB = 13 cm, then length of PQ will be
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- 8.5 cm
- 13 cm
- 12 cm
- 17 cm
- 8.5 cm
Correct Option: C
As per the given in question , we draw a figure of two circles of radii 11 cm and 6 cm 
Here , AB = 13 cm
PQ = √AB² - (r1 - r2)²
PQ = √13² - (11 - 6)²
PQ = √13² - 5² = √169 - 25
PQ = √144 = 12 cm.
