Answer:
Answer a) length = x - 2
Answer b) area = 6x - 12
Answer c) perimeter = 2x + 8
Explanation:
Any rectangle has a width and a length.
Given is width = 6 cm
The length is at this moment unknown, but we know something important. The length of this rectangle is 2 less than the diagonal. Lets call the length of the diagonal as x.
So although we do not actually know how long the diagonal is, we can still "pretend" it's value to be x. That is perfectly allowed, isn't it?
That way, the length = x-2. ( because that info was also given). Just don't worry to leave x in your answer :-).
Answer a) length = x - 2
So length = x - 2 and width = 6
The rest is easy!
area = width * length
area = 6 * (x - 2)
Answer b) area = 6x - 12
perimeter = 2 * width + ( 2 * length )
perimeter = 2 * 6 + ( 2 * (x - 2) )
perimeter = 12 + ( 2x - 4 )
perimeter = 2x + 8
Answer c) perimeter = 2x + 8