-
Two circles are of radii 7 cm and 2 cm their centres being 13cm apart. Then the length of direct common tangent to the circles between the points of contact is
-
- 12 cm
- 15 cm
- 10 cm
- 5 cm
- 12 cm
Correct Option: A
As per the given in question , we draw a figure of two circles with radii 7 cm and 2 cm , 
As we know that , Direct common tangent = √(Distance between two centres)² - (r1 - r2)²
Direct common tangent = √(C1C2)² -(r1 - r2)²
Direct common tangent = √(13)² - (7 - 2)²
Direct common tangent = √169 - 25
Direct common tangent = √144 = 12 cm.
