Estimating and Comparing Square Roots

Question

Which two numbers does lie between on a number line? 

7.7 and 7.8

7.8 and 7.9

7.9 and 8.0

8.0 and 8.1

Answer 1

There are many ways to accomplish this, and I don't know which one you've learned, but here's how I'd approach it:

8² = 64 so that eliminates choice 4 and probably choice 3, as well.

Now that you're down to two choices, guess and check:

7.8² = 60.84 That's close but too low, which means Answer 2 is correct.