Q.

In Fig, TA is a tangent to the circle with centre O such that OT = 4 cm, ∠OTA = 30°, then length of TA is:

1 23cm  
2 2 cm  
3 22cm  
4 3cm  

Ans.

(1)

Since TA is tangent at A and OA is radius of the circle,
OA  TA  OAT = 90°

 In right angled ΔOAT, we havecos30°=TAOT=32TA4=32TA=23 cm