The answer is: [D]: " 24 + 2w " . ___________________________________________ Explanation: ___________________________________________ Given: The formula for the Perimeter of a rectangle: ___________________________________________ P = 2L + 2w ;
in which: P = perimeter ; L = length = 12 units (given); w = width = unknown; _______________________________________________________ Find the perimeter, "P", in terms of "w" ; since "w" (width) is unknown; and considering the answer choices given; along with the information provided in the problem, we only have enough information to solve for the perimeter, "P", in terms of "w" ; _____________________________________________________ So, given the formula/equation for the perimeter, "P" : _____________________________________________________ P = 2L + 2w ; we know that: " L = 12 units " ; _____________________________________________________ P = 2*12 + 2w = 24 + 2w ; which is: "Answer choice: [D]" . _____________________________________________________