A square rug has an area of 80 ft2. Which is the best approximation of the length of one side of the rug?

Question

A square rug has an area of 80 ft². Which is the best approximation of the length of one side of the rug? 

1. A.7.5 ft
2. B.6.4 ft
3. C.8.9 ft
4. D.20 ft 

Answer 1

Formula for the area of a square: A=s^2. This is because all sides of a square are equal to each other. You plug in 80 for A and solve for s. To do this, take the square root of 80. If you do not have a calculator handy, to find and approximate perfect square of 80, find a perfect square near 80 and then decided if your answer is higher or lower.

The nearest perfect square to 80 is 81. the square root of 81 is 9, so because 80 is less than 81, you know that the square root of 80 has to be less than nine, and not by much.

Now, look at your answer choices, and find which number is closest to nine without going over. After reviewing your answer choice, you will see the answer is C. 8.9ft.

If you have any other questions, please send me a message so we can schedule a private tutoring session I hope this helps!

Answer 2

Since it is a square rug, all sides are equal. Area of a square is x², where x represents a side.

If A = x², then x = ±√A. We only need to take the positive value since this is a dimension.

x = √80.

80 = 16•5 and the square root of 16 = 4.

x = √(16•5) = 4√5, so we need to approximate √5 and multiply it by 4 to get an answer.

√4 = 2 and √9 = 3, thus √5 is between 2 and 3.

√80 will be between 8 and 12. Answer C), 8.9, is the only one between 8 and 12

You can check that by evaluating 8.9•8.9 = 79.21 which ≈ 80

Answer 3

square root of 80 = 2sqr20 = 4sqr5 = a little over 4(2.2) = about 8.9 feet, number 3 choice