So lets get to the problem
<span>165°= 135° +30° </span>
<span>To make it easier I'm going to write the same thing like this </span>
<span>165°= 90° + 45°+30° </span>
<span>Sin165° </span>
<span>= Sin ( 90° + 45°+30° ) </span>
<span>= Cos( 45°+30° )..... (∵ Sin(90 + θ)=cosθ </span>
<span>= Cos45°Cos30° - Sin45°Sin30° </span>
<span>Cos165° </span>
<span>= Cos ( 90° + 45°+30° ) </span>
<span>= -Sin( 45°+30° )..... (∵Cos(90 + θ)=-Sinθ </span>
<span>= Sin45°Cos30° + Cos45°Sin30° </span>
<span>Tan165° </span>
<span>= Tan ( 90° + 45°+30° ) </span>
<span>= -Cot( 45°+30° )..... (∵Cot(90 + θ)=-Tanθ </span>
<span>= -1/tan(45°+30°) </span>
<span>= -[1-tan45°.Tan30°]/[tan45°+Tan30°] </span>
<span>Substitute the above values with the following... These should be memorized </span>
<span>Sin 30° = 1/2 </span>
<span>Cos 30° =[Sqrt(3)]/2 </span>
<span>Tan 30° = 1/[Sqrt(3)] </span>
<span>Sin45°=Cos45°=1/[Sqrt(2)] </span>
<span>Tan 45° = 1</span>
<span>one way to solve this kind of problems is by doing a little bit of reversal
75 % * X = 54
75/100 * X = 54
(we move 75/100 to the right, since it's a fraction the top and bottom number will be reversed)
X = 54 * 100/75
X = 5400 / 75
X = 72 Hope I helped! :) Cheers!</span>
Answer:
Sales tax: 1.98465 which in this case is $1.98 (take note that you can round and it would be $2)
The total cost: $21.63 so no, Courtney cant buy the stuffed animal :(
Step-by-step explanation:
You can find the sales tax by dividing 10.1 by 100 to get 1.984...then rounding that number to get $1.98 since we are working with money in this problem then we have to find the total cost by adding our sales tax ($1.98) to our original cost ($19.65) to get our FINAL answer of $21.63
Hope this helped!!!!!
(i would appreciate being marked brainiest but it is ok if you don't)
