McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
4. Trigonometry
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Exercise 35 Page 656

Create an equation using the definition of the sine of an angle.

≈ 80 ft

Practice makes perfect

Let's begin with recalling the definition of the sine of an angle. If△ ABCis a right triangle with acute∠ A, then the sine of∠ Ais the ratio of the length of the leg opposite∠ Ato the length of the hypotenuse.

Now let's look at the given picture. We are given that the angle of ascent of the first hill of a roller coaster is 55^(∘), and the length of the track from the beginning of the ascent to the highest point is 98 feet. Let h be the height of the roller coaster.

Next, we can write that the sine of 55^(∘) is the ratio of the length of the opposite leg, h, to the length of the hypotenuse, 98. sin 55^(∘)=h/98 We can solve for h by evaluating sin 55^(∘) using a calculator.
sin 55^(∘)=h/98
Solve for h
98*sin55^(∘)=h
h=98*sin55^(∘)
h=98*0.8191...
h=80.2769...
h≈ 80
The height of the roller coaster when it reaches the top of the first hill is about 80 feet.