Embarking on a journey to master right triangle trigonometry? You've come to the right place. In this comprehensive guide, we'll delve into the world of sine, cosine, and tangent, providing you with a practice worksheet and a detailed answer key to help you grasp these essential concepts. Let's dive right in!
Understanding Right Triangle Trigonometry
Right triangle trigonometry is a fundamental branch of trigonometry that focuses on the relationships between the sides and angles of a right-angled triangle. The three primary trigonometric functions we'll explore are:
- Sine (sin): The ratio of the length of the side opposite an angle to the length of the hypotenuse.
- Cosine (cos): The ratio of the length of the side adjacent to an angle to the length of the hypotenuse.
- Tangent (tan): The ratio of the length of the side opposite an angle to the length of the side adjacent to that angle.
Practice Worksheet: Right Triangle Trigonometry
Before we dive into the answer key, let's test your understanding with a practice worksheet. Grab a pencil and paper, and tackle the following problems:

- In a right triangle with legs measuring 3 units and 4 units, find the length of the hypotenuse using the Pythagorean theorem. Then, calculate the sine, cosine, and tangent of the angle opposite the 3-unit side.
- Given a right triangle where the hypotenuse is 5 units long and the angle opposite the shorter leg is 37 degrees, find the lengths of the legs and the sine, cosine, and tangent of the 37-degree angle.
- In a right triangle with a hypotenuse of 8 units and an angle opposite the longer leg measuring 53 degrees, find the lengths of the legs and the sine, cosine, and tangent of the 53-degree angle.
Answer Key: Right Triangle Trigonometry
Problem 1
| Step | Calculation |
|---|---|
| 1 | Find the hypotenuse using the Pythagorean theorem: c² = a² + b² → c = √(3² + 4²) = 5 units |
| 2 | Calculate sine: sin(θ) = a/c = 3/5 |
| 3 | Calculate cosine: cos(θ) = b/c = 4/5 |
| 4 | Calculate tangent: tan(θ) = a/b = 3/4 |
Problem 2
| Step | Calculation |
|---|---|
| 1 | Find the length of the shorter leg using the sine function: a = c * sin(θ) = 5 * sin(37°) ≈ 2.93 units |
| 2 | Find the length of the longer leg using the Pythagorean theorem: b = √(c² - a²) ≈ 4.83 units |
| 3 | Calculate sine: sin(θ) = a/c ≈ 0.586 |
| 4 | Calculate cosine: cos(θ) = b/c ≈ 0.966 |
| 5 | Calculate tangent: tan(θ) = a/b ≈ 0.607 |
Problem 3
| Step | Calculation |
|---|---|
| 1 | Find the length of the shorter leg using the tangent function: b = a / tan(θ) = 8 / tan(53°) ≈ 9.54 units |
| 2 | Find the length of the longer leg using the Pythagorean theorem: a = √(c² - b²) ≈ 3.46 units |
| 3 | Calculate sine: sin(θ) = a/c ≈ 0.433 |
| 4 | Calculate cosine: cos(θ) = b/c ≈ 0.766 |
| 5 | Calculate tangent: tan(θ) = a/b ≈ 0.362 |
Mastering right triangle trigonometry is a crucial step in your mathematical journey. With practice and patience, you'll soon be tackling more complex problems with ease. Happy learning!