Hi guyz.
Would u explain these questions?

1. The points R, T, and U lie on a circle that has radius 4. If the length of arc RTU is 4pai/3, what is the length of line segment RU? anwer) 4


2. If d= 1/2^3 x 5^7 is expressed as a terminating decimal, how many nonzero digits will d have? answer) 2
(I got the answer but just calculate the denominator. other possible convenient approach?)


3.
1)Three pieces of wire have a median length of 48 inches. The other two wires' length are 44 and 48. What is the median?
Is it 48 or 46(median of 44 and 48) or just average? (This question is not a complete one. Sorry)
2)In the same manner, what is the median number of 44 45 45 48 48 ?


4. The operation @ is defined by x@y = 1/x + 1/y for all nonzero numbers x and y. if z is a number greater than 1, which of the following must be true?
1) z @ (-z) = 0
2) z @ z/z-1 = 0
3) 2/z @ 2/z =zd
A 1
B 1,2
C 1,3
D 2,3
E all
I thought it is A but the answelr is D. ur think?


5. is x<y ? (sorry this is DS)
1) the ratio of x to y is 7/9
2) xy>0
answer] E
My question is whether i can represent "the ratio of x to y" to x:y or x/y
And whether I can also use this with - figures.