Question

Solve for x. Round your answer to two decimal places.

Show work on how to get the answer please!

Answer 1

So, you know an angle measure, the opposite side from that angle, and the hypotenuse. What trig function relates those 3 parts?

Answer 2

\[\sin 39 = \frac{ 9 }{ x } \to x= \frac{ 9 }{ \sin39 }\]

Answer 3

and sin39 :

Answer 4

x = 14.51

Answer 5

is that the answer rounded two decimal places?

Answer 6

do you have MC ?
yes,sin 39 = 0.62 and 9/0.62 = 14.51

Answer 7

That's not quite the right answer. You shouldn't round in the intermediate steps.

Answer 8

then what should i do?

Answer 9

Well, first of all, you should HELP HER LEARN HOW to do the problem. Not do the whole thing for her. I was trying to do that.

But do get the answer with accuracy to 2 dec places, simply evaluate:

\(\Large \frac{ 9 }{ \sin39 }\)

You'll notice that the answer is slightly different (in the decimal part) than what you get, when you first round the sine value and use THAT in the computation.

Answer 10

In other words, don't evaluate the sine first and round THAT, and then put THAT back into the computation. Use "sin(39)" (or if you must do it 2 steps, then carry some extra decimal places in the intermediate step).

Answer 11

so it should be 14.30114156159175 ?

Answer 12

Also, you rounded the wrong way, compounding the error. sin(39*)=0.629320... which rounds to 0.63, not 0.62. But like I said, no good reason to round at all in the intermediate step.

Answer 13

Yes, rounded to 2 places.

But again, do you understand WHY? how to get that answer?

Answer 14

Do you want to try one more, just to make sure? :)

Answer 15

This is just a practice problem, its not for a test or anything. And yes im starting to understand,

Answer 16

No, its fine, im going to try some on my own now. But what is the answer rounded two decimals? im kind of confused on what you said about rounding

Answer 17

Just look at the 3rd decimal place. If that number is less than 5, leave the 2nd decimal place as-is. If it's 5 or greater, round the 2nd spot up.

Some examples, each rounded to 2 dec places:

2.534 rounds to 2.53
8.309 rounds to 8.31
3.497 rounds to 3.50
2.902 rounds to 2.90

Answer 18

so 14.30?

Answer 19

Yup. :)

Answer 20

Thank you both so much again!

Answer 21

and this example is very good to learn:
7.455 rounds to 7.46

@DebbieG , Thank you so much :)