What is the exact value of the square root of 28 over 9 the square root of 16.? Simplify if possible.
\[\frac{\sqrt{28}}{9\sqrt{16}}\]
yes
You already know the square root of 16. What is it?
um 8?
oops 4
Okay, so now you have \[\frac{\sqrt{28}}{9 \dot\ 4}\]
um 36
\[\frac{\sqrt{28}}{36}\]
Now think of two numbers that multiply to get 28. One of those numbers needs to be a perfect square.
um 2 and 14
Neither of those numbers are a perfect square.
okk?
So think of two other numbers.
7 and 4
Do you know which one of those are a perfect square?
4
Do you know why it is 4?
because 2 goes in it evenly
Because, in general: `A perfect square is a number such that n x n = n^2, with n^2 being the perfect number.`
okkkaaayyy :)
Anyway, so now we can re-write the fraction like so: \[\frac{\sqrt{4 \dot\ 7}}{36}\]
One rule of radicals states the following: `The square root of a x b equals the square root of a times the square root of b:` \[\sqrt{a \times b} = \sqrt{a} \times \sqrt{b}\] Knowing this, how can we re-write the numerator?
i dont know? :(
oh wait would it be sqrt7 and sqrt 4?
\[\frac{1}{9}\sqrt{\frac{28}{16}}=\frac{1}{9}\sqrt{\frac{7}{4}}=\frac{\sqrt{7}}{18} \]
Yes, correct, so \[\frac{\sqrt{4} \dot\ \sqrt{7}}{36}\]
ok
Now, you know the square root of 4. What is it?
2
So now, we have, \[\frac{ 2\sqrt{7}}{36}\]
oookkk
We can rewrite 36 as 2 x 18 to get \[\frac{ 2\sqrt{7}}{2 \dot\ 18}\]
Now what can we cancel in that fraction above?
sqr7 over 18!!! thank you!!!!!! <333
You cancel 2/2 to get the answer you mentioned, yet
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