Hey there! I'm happy to help!
Since this mural is a square, all the sides are the same. This means that you square on of the sides to get the area (multiply it by itself). If we have the area and want to find a side, we just go backwards and use something called the square root!
If we plug this into our calculators...
√138≈11.74734
We see that is closest to B. 12 ft.
You could also figure this out without a calculator. 138 is very close to 144, which is 12². All the other answer options are way too big.
Have a wonderful day! :D
Answer:
The probability that the next mattress sold is either king or queen-size is P=0.8.
Step-by-step explanation:
We have 3 types of matress: queen size (Q), king size (K) and twin size (T).
We will treat the probability as the proportion (or relative frequency) of sales of each type of matress.
We know that the number of queen-size mattresses sold is one-fourth the number of king and twin-size mattresses combined. This can be expressed as:

We also know that three times as many king-size mattresses are sold as twin-size mattresses. We can express that as:

Finally, we know that the sum of probablities has to be 1, or 100%.

We can solve this by sustitution:

Now we know the probabilities of each of the matress types.
The probability that the next matress sold is either king or queen-size is:

Answer:
I'm not even lying, it's none of them ;-;
btw if you want, can you give me brainliest :((