The phrase "twice the difference of a number and 5" can be written as which variable expression?

Let the unknown number be x.

Hence,

Twice the difference of a number and 5 = 2 * (x - 5) = 2(x - 5) = 2x - 10

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's