You have to say what or where point B and C is for me to answer it
Sin means to divide the opposite side measure by the hypotenuse. Cos is equal to the adjacent side value divided by the hypotenuse. Tan is equal to the opposite value divided by the adjacent. To remember this, I use the abbreviation SOHCAHTOA. SOH for Sin is Opposite over Hypotenuse, and so on.
The easy way to think about this is what number comes between 5 and 7? The answer is 6 (but we have to consider that it's negative in this case.) So the answer is -6 Another way to look at it is with a number line (not to "Which number is greater than -7 and less than -5"? scale.)<===(-7)==(-6)==(-5)==(-3)==(-2)==(-1)==(0)==(1)==>Notice how -6 comes between the two numbers. -6 is larger than -7 (it's "less negative" -- "Which number is greater than -7 and less than -5"? closer to zero) -6 is less than -5 (it's "more negative" -- further away from zero)
Put this in your calculator or use pictures if you'd like. (3/4) x 12 and you'll get 9
