Question

In ABC, C is a right angle, what is the measure of x?

Answer 1

A cosine function would help you with that. Are you equipped to utilize such a function?

Answer 2

I have a calc

Answer 3

Great. Make sure it is in degree mode and find the inverse cosine of 8/21.

Answer 4

do I use the cos^-1?

Answer 5

That's right. If you get 1.18, or close to it, your calculator is in Radian Mode and you will need to figure out how to change it to Degree mode.

Answer 6

is it 30

Answer 7

Is what 30? What are the units with that? Did you divide 8/21? What did you get? Exactly what keys did you press to get that result?

Answer 8

Im sorry Im looking at the wrong question....67.6

Answer 9

If you hold down the [alt] key, and while holding it down, press on the numeric keypad 0 1 8 6, you can achieve he degree symbol. 67.6º

Answer 10

That doesnt work on my laptop

Answer 11

Fair enough. You do need a separate numeric keypad. Anyway, good work. You find 67.6º using the inverse cosine function.

Do you understand why we used that button? You should be familiar with the right triangle definition of sine, cosine, and tangent.

Answer 12

Im just startin to get the hang of it

Answer 13

Well, given an acute angle (call it \(\alpha\)) of a right triangle, we have \(\cos(\alpha) = \dfrac{Adjacent\;Leg}{Hypotenuse}\). This is why I suggested the cosine function and 8/21. You will be expected to know this definition and usage.

Good work. Keep plugging away. You'll get it.

Answer 14

thanks