Question

Look at th figure. What is the length of AC?

Answer 1

22.6 inches

16 inches

32 inches

11.3 inches

Answer 2

What is the length of AC?

Answer 3

I mean AD

Answer 4

Im not sure. i dont really get it.

Answer 5

DCA is 45 degrees and CDA is 90 degrees OK?

Answer 6

okay

Answer 7

So what is DAC?

Answer 8

in degrees?

Answer 9

Sure

Answer 10

180 - 90 - 45 = ?

Answer 11

45

Answer 12

So what kind of triangle is triangle DAC?

Answer 13

a special right triangle?

Answer 14

Yes, it's an isosceles triangle. You know about those?

Answer 15

yeah, those are the opnes that have 2 equal side. right?

Answer 16

Yes, which two sides?

Answer 17

Side CB and CA?

Answer 18

We're talking about the small inside triangle DAC.
But you're right, the big triangle is also isosceles.

Answer 19

ok, so i would say CD and DA?

Answer 20

Great! CD = DA
Now what?

Answer 21

What is the unknown?

Answer 22

the measures of them both

Answer 23

Read the problem again.

Answer 24

oh! i have to figure out what AC is

Answer 25

How?

Answer 26

um.. im not sure because they dont give you any measurments at all.

Answer 27

What else do you know that's special about triangle DAC?

Answer 28

That we would only have to find one of the other sides and we could do the pathagorem thoerem. so how ever you spell it. lol

Answer 29

Since DAC has a right angle in it, it's a right triangle, and you can use Pythagoras.
What is the theorem?

Answer 30

i have no idea.

Answer 31

http://en.wikipedia.org/wiki/Pythagorean_theorem
I'll wait.

Answer 32

a^2+b^2=c^2?

Answer 33

Yes.

Answer 34

Which side is c in this problem?

Answer 35

AC?

Answer 36

OK. So set up the equation for me

Answer 37

16^2+b^2=c^2?

Answer 38

Let's do it in terms of the triangle in the problem. Let me help OK?

Answer 39

actually b wouold 16 too

Answer 40

Yes

Answer 41

so it would really be 512=c^2?

Answer 42

That's what I get.

Answer 43

okay, so then the answer would be 22.6

Answer 44

Seems right.
Great job!

Answer 45

thanks

Answer 46

yw