[" 57.If "r:R:r_(1)=2:5:12," then "A=],[[" 1) "45^(@)," 2) "60^(@)," 3) "30^(@)," 4) "90]]

In Delta ABC, if r:R:r_1=2:5:12 , then A=

If r : R r_1 = 2: 5 : 12 then angle A =

If r_(1)=8, r_(2)= 12r_(3)=24 then C=

If P(5,r)=2,P(6,r-1), find r

If ""^(12)C_(5) =^(12)C_(r) then r=_____

Let A = (1,2,3) and R = (1,1), (2,2), (1,2), (2,1), (1,3) then R is

I : IF ""^(12)C_(r+1) ="" ^(12) C_(3r-5) then r=3 or 4 . II : If ""^(9) C_(3) +""^(9)C_(5) = ""^(10)C_(r) then r=4 or 6.

If ""^(n)C_(r-1):""^(n)C_(r):""^(n)C_(r+1)=2:4:5 then (n,r) is