ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos

ACT Math 1.3 Pre-Algebra 542 Views


Share It!


Description:

ACT Math Pre-Algebra Drill 1, Problem 3. Can you find the product of two square roots?

Language:
English Language

Transcript

00:03

Here's an unshmoopy question you'll find on an exam somewhere in life...

00:06

Calculate the square root of 32 times the square root of 8.

00:10

And here are the potential answers...

00:15

OK, so this question is really all about factors

00:17

-- can we recognize and use them?

00:19

We'll rarely be asked to calculate a square root that doesn't come out even on a test like this...

00:24

...so if we feel like we've been backed into that corner of actually having to calculate it...

00:28

...we may have messed up somewhere upstream.

00:30

That's not to say they won't ever throw a weird one in there,

00:33

but... it's just something to keep in mind.

00:35

So, in this case we have to think about the factors

00:37

of 32... 2 and 16 and 4 and 8.

00:42

First we have the square root of 32. What perfect squares go into 32 evenly?

00:47

Well, 4 does... but the bigger the better, in this case anyway...

00:51

16 times 2 equals 32, and 16 is 4 squared.

00:55

So we can rewrite this as the square root of 16 times 2, then we can pull out a 4 to

01:00

make it 4 square root of 2.

01:03

Next on the docket is the square root of 8. Now 4 is the best we can do.

01:07

The square root of 4 times 2 can be rewritten as 2 square root of 2.

01:12

When we multiply these two together, we get 4 times 2 is 8...

01:17

...and then square root of 2 times square root of 2 is... 2.

01:22

Multiply those two numbers together, and we're left with 16...

01:25

So the answer C.

01:25

As in, "Calculating villains."

Up Next

ACT Math 3.1 Plane Geometry
2558 Views

ACT Math: Plane Geometry Drill 3, Problem 1. What is the area of the trapezoid shape in the video?

Related Videos

Inequalities in Number Lines
3224 Views

ACT Math: Coordinate Geometry Drill 1, Problem 1. Which inequality is expressed by the number line?

ACT Math 3.1 Intermediate Algebra
1954 Views

ACT Math: Intermediate Algebra: Drill 3, Problem 1. Find the fifth number in the series.

Simplifying Radicals
9737 Views

We don't like knocking people down to size, but we do like simplifying radicals. Join us?

Arithmetic Math
2248 Views

If fleeing criminals always fled the scene of the crime at perfect right angles, it would be much easier to determine their whereabouts. Fortunatel...