Question

the distance between the points (2,15°) and (1,75°) is

Answer 1

                    solution

   using  

 r=r₁²+r₂²-2abcos∅

   where r₁=2     and     r₂=1                    ∅=75-15=60°

 ⇒ r=2²+1²-2*2*1cos60

⇒ r=4+1-4*1/2

⇒ r=5-4/2

⇒ r=5-2

⇒ r=3 unit

⇒ the distance between the points is required as 3 unit