How to do number a and d?

help please

a. Let's call the first number x which would make the other 2 numbers x + 2 and x + 4. Since they have a sum of 54 we can write:

x + x + 2 + x + 4 = 54

3x + 6 = 54

3x = 48

x = 16 so the numbers are 16, 18, 20.

d. We can write:

30 + x = 4(3 + x)

30 + x = 12 + 4x

18 = 3x

x = 6 years

In order for the room to be a square, all sides must be the same length. In order to determine if all sides are equal, you need to use the formula A2 +B2 = C2 where 2 is the power that A, B, and C are being raised to. You would the have A2 + 13(2) = 15.26(2). If you do not want to solve for that just plug in so that both sides are equal 13(2) + 13(2) = C2
13(2) + 13(2) =338
Then you have to square that value to find the answer. The square root of 338 is 18.384. That is not the value of the corner to corner diagonal, therefore the answer is that the shape is not a square.