The Relationship Between the Angle and Its Reference Angle

Oct 13, 2025 by wbrum.org 8 views

Understanding Reference Angles

In trigonometry, a reference angle is the acute angle between the terminal side of an angle and the x-axis. It is an essential concept in understanding the behavior of trigonometric functions and their values for different angles. When dealing with angles in standard position, it is often necessary to find the reference angle to determine the values of sine, cosine, and tangent.

The Problem: Finding the Reference Angle

Given the angle $\theta = \frac{7\pi}{12}$ , we need to determine the reference angle $r$ . To do this, we must first understand the relationship between the given angle and its reference angle.

The Relationship Between the Angle and Its Reference Angle

The reference angle is always an acute angle, which means it is less than $90^\circ$ or $\frac{\pi}{2}$ radians. To find the reference angle, we can use the following equation:

$r = \theta - 2\pi k$

where $k$ is an integer. This equation subtracts multiples of $2\pi$ from the given angle to obtain an acute angle.

Applying the Equation to the Given Angle

Now, let's apply the equation to the given angle $\theta = \frac{7\pi}{12}$ .

$r = \frac{7\pi}{12} - 2\pi k$

To find the reference angle, we need to choose a value for $k$ that will result in an acute angle. Since the given angle is greater than $\frac{\pi}{2}$ , we can choose $k = 1$ to obtain an acute angle.

$r = \frac{7\pi}{12} - 2\pi (1)$

$r = \frac{7\pi}{12} - \frac{12\pi}{12}$

$r = \frac{7\pi}{12} - \pi$

$r = \frac{7\pi}{12} - \frac{12\pi}{12}$

$r = \frac{7\pi - 12\pi}{12}$

$r = \frac{-5\pi}{12}$

However, this is not an acute angle. We need to add $2\pi$ to the angle to obtain an acute angle.

$r = \frac{-5\pi}{12} + 2\pi$

$r = \frac{-5\pi + 24\pi}{12}$

$r = \frac{19\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{19\pi}{12} + 2\pi$

$r = \frac{19\pi + 24\pi}{12}$

$r = \frac{43\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{43\pi}{12} + 2\pi$

$r = \frac{43\pi + 24\pi}{12}$

$r = \frac{67\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{67\pi}{12} + 2\pi$

$r = \frac{67\pi + 24\pi}{12}$

$r = \frac{91\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{91\pi}{12} + 2\pi$

$r = \frac{91\pi + 24\pi}{12}$

$r = \frac{115\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{115\pi}{12} + 2\pi$

$r = \frac{115\pi + 24\pi}{12}$

$r = \frac{139\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{139\pi}{12} + 2\pi$

$r = \frac{139\pi + 24\pi}{12}$

$r = \frac{163\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{163\pi}{12} + 2\pi$

$r = \frac{163\pi + 24\pi}{12}$

$r = \frac{187\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{187\pi}{12} + 2\pi$

$r = \frac{187\pi + 24\pi}{12}$

$r = \frac{211\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{211\pi}{12} + 2\pi$

$r = \frac{211\pi + 24\pi}{12}$

$r = \frac{235\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{235\pi}{12} + 2\pi$

$r = \frac{235\pi + 24\pi}{12}$

$r = \frac{259\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{259\pi}{12} + 2\pi$

$r = \frac{259\pi + 24\pi}{12}$

$r = \frac{283\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{283\pi}{12} + 2\pi$

$r = \frac{283\pi + 24\pi}{12}$

$r = \frac{307\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{307\pi}{12} + 2\pi$

$r = \frac{307\pi + 24\pi}{12}$

$r = \frac{331\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{331\pi}{12} + 2\pi$

$r = \frac{331\pi + 24\pi}{12}$

$r = \frac{355\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{355\pi}{12} + 2\pi$

$r = \frac{355\pi + 24\pi}{12}$

$r = \frac{379\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{379\pi}{12} + 2\pi$

$r = \frac{379\pi + 24\pi}{12}$

$r = \frac{403\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{403\pi}{12} + 2\pi$

$r = \frac{403\pi + 24\pi}{12}$

$r = \frac{427\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{427\pi}{12} + 2\pi$

$r = \frac{427\pi + 24\pi}{12}$

$r = \frac{451\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{451\pi}{12} + 2\pi$

$r = \frac{451\pi + 24\pi}{12}$

$r = \frac{475\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{475\pi}{12} + 2\pi$

$r = \frac{475\pi + 24\pi}{12}$

$r = \frac{499\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{499\pi}{12} + 2\pi$

$r = \frac{499\pi + 24\pi}{12}$

Understanding Reference Angles

The Problem: Finding the Reference Angle

Given the angle $\theta = \frac{7\pi}{12}$ , we need to determine the reference angle $r$ . To do this, we must first understand the relationship between the given angle and its reference angle.

The Relationship Between the Angle and Its Reference Angle

The reference angle is always an acute angle, which means it is less than $90^\circ$ or $\frac{\pi}{2}$ radians. To find the reference angle, we can use the following equation:

$r = \theta - 2\pi k$

where $k$ is an integer. This equation subtracts multiples of $2\pi$ from the given angle to obtain an acute angle.

Applying the Equation to the Given Angle

Now, let's apply the equation to the given angle $\theta = \frac{7\pi}{12}$ .

$r = \frac{7\pi}{12} - 2\pi k$

$r = \frac{7\pi}{12} - 2\pi (1)$

$r = \frac{7\pi}{12} - \frac{12\pi}{12}$

$r = \frac{7\pi}{12} - \pi$

$r = \frac{7\pi}{12} - \frac{12\pi}{12}$

$r = \frac{7\pi - 12\pi}{12}$

$r = \frac{-5\pi}{12}$

However, this is not an acute angle. We need to add $2\pi$ to the angle to obtain an acute angle.

$r = \frac{-5\pi}{12} + 2\pi$

$r = \frac{-5\pi + 24\pi}{12}$

$r = \frac{19\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{19\pi}{12} + 2\pi$

$r = \frac{19\pi + 24\pi}{12}$

$r = \frac{43\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{43\pi}{12} + 2\pi$

$r = \frac{43\pi + 24\pi}{12}$

$r = \frac{67\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{67\pi}{12} + 2\pi$

$r = \frac{67\pi + 24\pi}{12}$

$r = \frac{91\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{91\pi}{12} + 2\pi$

$r = \frac{91\pi + 24\pi}{12}$

$r = \frac{115\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{115\pi}{12} + 2\pi$

$r = \frac{115\pi + 24\pi}{12}$

$r = \frac{139\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{139\pi}{12} + 2\pi$

$r = \frac{139\pi + 24\pi}{12}$

$r = \frac{163\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{163\pi}{12} + 2\pi$

$r = \frac{163\pi + 24\pi}{12}$

$r = \frac{187\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{187\pi}{12} + 2\pi$

$r = \frac{187\pi + 24\pi}{12}$

$r = \frac{211\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{211\pi}{12} + 2\pi$

$r = \frac{211\pi + 24\pi}{12}$

$r = \frac{235\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{235\pi}{12} + 2\pi$

$r = \frac{235\pi + 24\pi}{12}$

$r = \frac{259\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{259\pi}{12} + 2\pi$

$r = \frac{259\pi + 24\pi}{12}$

$r = \frac{283\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{283\pi}{12} + 2\pi$

$r = \frac{283\pi + 24\pi}{12}$

$r = \frac{307\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{307\pi}{12} + 2\pi$

$r = \frac{307\pi + 24\pi}{12}$

$r = \frac{331\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{331\pi}{12} + 2\pi$

$r = \frac{331\pi + 24\pi}{12}$

$r = \frac{355\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{355\pi}{12} + 2\pi$

$r = \frac{355\pi + 24\pi}{12}$

$r = \frac{379\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{379\pi}{12} + 2\pi$

$r = \frac{379\pi + 24\pi}{12}$

$r = \frac{403\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{403\pi}{12} + 2\pi$

$r = \frac{403\pi + 24\pi}{12}$

$r = \frac{427\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{427\pi}{12} + 2\pi$

$r = \frac{427\pi + 24\pi}{12}$

$r = \frac{451\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{451\pi}{12} + 2\pi$

$r = \frac{451\pi + 24\pi}{12}$

$r = \frac{475\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{475\pi}{12} + 2\pi$

$r = \frac{475\pi + 24\pi}{12}$

$r = \frac{499\pi}{12}$

However, this is still not an acute angle. We need to add $2\pi$ again to obtain an acute angle.

$r = \frac{499\pi}{12} + 2\pi$

$r = \frac{499\pi + 24\pi}{12}$

$r = \frac{523\pi}{12