All Trigonometry Resources
Example Questions
Example Question #1 : Law Of Sines
What is the measure of in below? Round to the nearest tenth of a degree.
The law of sines tells us that , where a, b, and c are the sides opposite of angles A, B, and C. In , these ratios can be used to find :
Example Question #1 : Law Of Sines
Find the length of the line segment in the triangle below.
Round to the nearest hundredth of a centimeter.
The law of sines states that
.
In this triangle, we are looking for the side length c, and we are given angle A, angle B, and side b. The sum of the interior angles of a triangle is ; using subtraction we find that angle C = .
We can now form a proportion that includes only one unknown, c:
Solving for c, we find that
.
Example Question #1 : Law Of Sines
In the triangle below, , , and . What is the length of side to the nearest tenth?
First, find . The sum of the interior angles of a triangle is , so , or .
Using this information, you can set up a proportion to find side b:
Example Question #1 : Law Of Sines
In the triangle below, , , and .
What is the length of side a to the nearest tenth?
To use the law of sines, first you must find the measure of . Since the sum of the interior angles of a triangle is , .
Law of sines:
Example Question #11 : Law Of Sines
The triangle above has side lengths 3, 4, and 6. The angle opposite the side of length 6 measures 117.28 degrees, rounded to the nearest hundredth. Angle is opposite the side of length 3. What is the measure of , rounded to the nearest hundredth of a degree?
Because the angle with measure 117.28 degrees is opposite the side of length 6, and angle is opposite the side of length 3, we can use the Law of Sines to solve for the measure of .
Example Question #12 : Law Of Sines
Find the length of side a using the law of sines. All angles are in degrees.
The law of sines states that, given a triangle with sides a, b, and c and angles A, B, and C opposite to the corresponding sides,
Since the sides and angles given are directly opposite, we can use the law of sines.
Solving for a, we get
Evaluating the expression, we find that
Example Question #82 : Triangles
Find the measure of angle A.
The law of sines states that, given a triangle, the following relationship is always true:
where a, b, and c are sides and A, B, and C are the angles opposite to the sides.
This problem does not give us the length of the side opposite to the angle we want to find, so we have to find it indirectly.
We start by finding the measure of the unmarked angle, which we'll represent as B:
Solving for , we get
Now that we have the measures of two angles, we can find the measure of the third by the theorem:
Example Question #14 : Law Of Sines
Find the length of side .
Recall the Law of Sines:
Start by finding the value of angle :
Plug in the given values into the Law of Sines:
Rearrange the equation to solve for :
Make sure to round to two places after the decimal.
Example Question #83 : Triangles
Find the length of side
Recall the Law of Sines:
Start by finding the value of angle :
Plug in the given values into the Law of Sines:
Rearrange the equation to solve for :
Make sure to round to two places after the decimal.
Example Question #13 : Law Of Sines
Find the length of side .
Recall the Law of Sines:
Start by finding the value of angle :
Plug in the given values into the Law of Sines:
Rearrange the equation to solve for :
Make sure to round to two places after the decimal.