Question

Answer based on the following
Two circles of radii $8$ units and $4$ units are drawn. The distances between there centres is $20$ units.
What is the length of transverse common tangent?

• A. $16$ units
• B. $12$ units
• C. $8\sqrt{6}$ units
• D. $32$ units

Answer 1

Answer: (A)

$16$ units

$C_1{C}_2=20$
No of direct common tangents
No of inverse common tangents $=2$
Length of inverse common tangent $=\sqrt{{20}^2-(8+4{)}^2}$
$=4\sqrt{25-9}=16$