Math Problem Statement

Find the reference angle for a rotation of start fraction, 2, pi, divided by, 9, end fraction92π​.

Solution

To find the reference angle for a given rotation, we first need to determine whether the angle is already within the range 00^\circ to 360360^\circ (or 00 to 2π2\pi radians) and then find the corresponding reference angle.

The given rotation angle is 92π9\frac{92\pi}{9}.

Step 1: Simplify the Angle

We want to reduce the angle within the standard interval of [0,2π][0, 2\pi]. To do this, we find the equivalent angle by subtracting multiples of 2π2\pi.

Let's first divide 92π9\frac{92\pi}{9} by 2π2\pi:

92π92π=929×12=9218=5.11\frac{\frac{92\pi}{9}}{2\pi} = \frac{92}{9} \times \frac{1}{2} = \frac{92}{18} = 5.11

So, 92π9\frac{92\pi}{9} is approximately 5.115.11 full rotations of 2π2\pi.

Now, subtract the integer part (5 full rotations) to find the remaining portion of the angle: 5.115=0.115.11 - 5 = 0.11 Now, multiply 0.110.11 by 2π2\pi to get the angle within one full revolution: 0.11×2π=0.22π0.11 \times 2\pi = 0.22\pi

Step 2: Reference Angle

The simplified angle is 0.22π0.22\pi. Since this angle is already between 00 and π\pi, it is in the first quadrant, and therefore the reference angle is simply 0.22π0.22\pi.

Thus, the reference angle is: 0.22π radians.0.22\pi \text{ radians}.

Would you like a further breakdown or any clarifications on this?

Here are 5 related questions for further exploration:

  1. How do you calculate the reference angle for angles greater than 2π2\pi?
  2. What is the relationship between reference angles and trigonometric function values?
  3. How can you convert radians to degrees for easier interpretation?
  4. What is the reference angle for 15π4\frac{15\pi}{4}?
  5. How do negative angles affect the reference angle?

Tip: The reference angle is always positive and lies between 00 and π2\frac{\pi}{2} radians or 00^\circ and 9090^\circ.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Angle Measures
Radian Measure
Reference Angle

Formulas

Reference angle formula: Angle - 2nπ (where n is the number of full rotations)
Multiplying fractions to simplify rotation: 0.11 × 2π

Theorems

Reference Angle Theorem
Modulus of an angle

Suitable Grade Level

Grades 10-12