First, you must know the definition of prime number which is any number above one that has no factors other than 1 and itself (examples: 2,3,5,7,etc) and composite has the opposite meaning
So look at the factors of 68:
1,2,4,17,34,68
It has factors other than 1 and itself
So that means 68 is a composite number
The answer for the binary number 10101 is 21
The interior angel to ∠7 is the angel ∠4
because ∠7 + ∠4 = 180°
The correct choice is number 1
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