Distance Of Closest Approach

Two particles are moving along two long straight lines,in the same plane with the same speed = 20 cm/sec . The angle between the two lines is 60 degree , and their intersection point is O . At a certain moment , the two particles are located at distances 3 m and 4 m from O and are moving towards O . If The Shortest distance between them subsequently can be expressed in the form of $\sqrt{a}$ . where a is a positive integer and not a square of integer. then find the sum of digits in a . Give Your Answer in centimeter(cm). Assumptions Take g = 10 m/sec^2 If needed cos 30 = $\sqrt{3}$ /2 sin 30 = 1/2 tan 30 = $\sqrt{3}$ All the above angles are in degrees. This Question Is Not Original