36. (i) express the following in litres.
(a) 30ml
(b) 3ml
(ii) find : 4.9 = 7​

Let the length of the arc be l cm. 

given conditions  ⇒
  angle (θ) = 3π/5 
pie in the question shows that the angle is in radians. 

radius(r) = 7 cm. 

using the formula, 
     

where,  θ (or angle) is in the radians) 

∴ length of the arc = 3π/5  × 7
    = 3  × 22/35  × 7    [∵  π =22/7] 
    = 3  × 22/5
    = 66/5
           

hence, the length of the arc is 13.2 cm. 

hope it . 

In 10 sec = 23
in 1 minute = 23*6=138
in 2 sec= 23*12=276