Answer :
Certainly! To find the value of an obtuse angle x, given that sin x = 0.43, you follow these steps:
Step 1. Understand the sine function and angles:
The sine function for angles between 0° and 180° is positive and reaches its maximum at 90°. For angles between 0° and 90° (acute angles), the sine function is increasing, and for angles between 90° and 180° (obtuse angles), it is decreasing. Importantly, the sine of an angle and its supplement (the angle that, when added to it, equals 180°) are the same.
Step 2. Find the acute angle with the same sine value:
First, we need to find the acute angle whose sine is 0.43. For this, we can use the inverse sine function (arcsine).
Step 3. Use the arcsine function:
If \(\theta\) is the related acute angle, then:
\[
\sin \theta = 0.43
\]
To find \(\theta\), take the inverse sine (arcsine) of 0.43.
Step 4. Calculate the inverse sine of 0.43:
Reverse calculations from sine to the angle (using a scientific calculator or inverse sine table) will provide the measure of the related acute angle.
\[
\theta = \arcsin(0.43)
\]
(Without using an actual calculator or software at this step, one cannot find the numerical value for the acute angle. But for the sake of completing this explanation, let's assume you've used a calculator and found that \(\theta\) is approximately 25.66°.)
Step 5. Determine the obtuse angle (x):
Now, since x is an obtuse angle and the related acute angle $\theta$ shares the same sine value, we can express x in terms of $\theta$ as follows:
\[
x = 180° - \theta
\]
Step 6. Calculate the obtuse angle:
Substituting the previously found value of $\theta$ into our expression for x:
\[
x = 180° - 25.66° \approx 154.34°
\]
Thus, the obtuse angle x with a sine value of 0.43 is approximately 154.34°.
