Geometry Practice Test 3

Question : 15 of 40

Marks: +1, -0

The distance between the centres of the two circles with radius 4 cm and 9 cm is 13 cm. The length of the direct common tangent (between two points of contact) is:

13 cm
$√{153}$ cm
12 cm
18 cm

Validate

Solution:

Length of the direct common tangent =

√{d^2-(r_1-r_2)^2}

√{(13)^2-(9-4)^2}

√{169-25}

√{144}

= 12 cm

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