Law of sines graphic organizer law of sines missing side missing angle ambiguous case steps ambiguous case no solution ambiguous case 2 solutions ambiguous case 1 solution b 102 c 43 b 21 a 42 a 22 b 12 1. This lesson covers the ambiguous case of the law of sines. Eleventh grade lesson ambiguous case day 1 of 2 betterlesson. For those of you who need a reminder, the ambiguous case occurs when one uses the law of sines to determine missing measures of a triangle when given two sides and an angle opposite one of those angles ssa. How can the law of sines be used in problems involving the ambiguous case.
The sine function is positive in the first and second quadrant, but calculators are designed to display the first angle as a result. Ssa is known as the ambiguous case when using the law of sines because the given information may result in one triangle, two triangles, or no triangle at all. We also discovered that ssa did not work to prove triangles. Teaching this particular topic in the past has created numerous headaches for both me and my students. Proof of the law of sines this is a topic in traditional trigonometry. Furthermore, as a result, you might have to analyze the situation before applying the law of sines and solving for the missing pieces. Find all solutions for triangle and round to nearest tenth. Dec 22, 2016 ambiguous case law of sines in geometry, we found that we could prove two triangles congruent using. Beyond right angle trigonometry when we first started talking about.
Find the if shown in quadrant i is angle a with a sine of. Keep on lengthening side a until there are two possible triangles formed by the given info this is know as the ambiguous case. The sides of a triangle are to one another in the same ratio as the sines of their opposite angles. Proof of the law of sines w e use the law of sines and the law of cosines to solve triangles that are not rightangled. There is another possible answer to this question and that is the coterminal angle of 106. T he law of sines allows us to solve triangles that are not rightangled, and are called oblique triangles. The ambiguous case ssa if we are given two sides and an angle opposite one of the two sides ssa, the given information may result in one triangle, two triangles, or no triangle at all. Plan your 60minute lesson in math or law of sines with helpful tips from katharine sparks. Use the law of sines to find measure of angle a in this scenario. Because c is obtuse and the side opposite c is longer than the given adjacent side, you know that only one triangle can be formed. Free printable worksheet plus answer key on the ambiguous case of the law of sines includes visual aides, model problems, an online component and. The law of sines can be used to solve for sides and angles of oblique triangles. This concept is often difficult for students to visualize because it involves turning one triangle into two when certain conditions are met. Law of sines and law of cosines math lib bundle math lib activities are a class favorite.
One reallife application of the sine rule is the sine bar, which is used to measure the angle of a tilt in engineering. After analyzing the ambiguous case for oblique triangles students will determine the number of possible solutions and find solutions when possible. The law of sines relates all angles and sides of a triangle in the following way, in which the lowercase letters indicate the side directly across from the capitalized angle. Because, ssa triangles can yield us one triangle, two triangles, or no triangles. Prior to applying the law of sines, one should find h using the product of the sine of the known angle and the noncorresponding. In the ssa case given two sides and the angle opposite one of the sides 3 possibilities exist. By downloading this file you are agreeing to the terms of use.
We know that this triangle is a candidate for the ambiguous case since we are given two sides and an angle not in between them. When using the law of sines to find a side of a triangle, an ambiguous case occurs when two separate triangles can be constructed from the data provided i. This is a big part of using the law of sines cases where the given data can produce more than one triangle particularly when the given data is ssa. Ill try to make it look a little strange so you realize it can apply to any triangle. For this project, i decided to demonstrate a trigonometric concept. When using the law of sines to find a side of a triangle, an ambiguous case occurs when. Lesson 3 ambiguous case of sine law ssa occurs when you are given ssa but the triangle is not constructed depending on the measure of the angle and the lengths of the sides, it may be possible to construct and therefore solve 0, 1, or 2 triangles. Ambiguous case of law of sines worksheet pdf with answer key. What quantities should you check before applying the law of sines. In the case shown below they are triangles abc and ab. The ambiguous case ssa occurs when we are given two sides and the. Given two sides and an angle opposite one side ssa triangle.
If you are given two sides and a nonincluded acute angle and the side facing the given angle is less than the other side, you would obtain two sets of answers. If it helps, you can draw a rough sketch to view this triangle, but this is optional. In its default state, the side length a is clearly not long enough to form a real triangle. Use the law of sines to find missing angles and sides of a nonright triangle. Such triangles are called oblique or scalene triangles. So, there are situations where the information were provided with for a triangle make it possible for. A 40o a b c a b c 20 in 20 in 25 in 25 in 40o 40o 2 possible pictures if b 53. This situation is also known as the ambiguous case.
So, if we encounter a triangle that has ssa congruency, we have an ambiguous triangle in the sense that we need to investigate more thoroughly. We will now consider the situation when we are given two sides and one angle of a triangle ambiguous case. Students will understand when the law of sines can be used to. Other common examples include measurement of distances in navigation and measurement of the distance between two stars in astronomy. Understanding and solving the ambiguous case for the law of sines has never been easier with this sure fire method and 7 detailed. Jan 21, 2020 ambiguous means that something is unclear or not exact or open to interpretation.
This law of sines law of cosines foldable flip book is designed for geometry, algebra 2, or precalculus depending upon curriculum. One book includes the ambiguous case of the law of sines, and the other does not. Given two sides and a nonincluded angle of a triangle, you might not be able to determine what type of triangle it is, or even if those pieces form a triangle at all. What links here related changes upload file special pages permanent link. Model problems in the following example you will find the possible measures of an angle given the sine of the angle. The ssa caseone triangle solve abc with c 122, a 12 cm, and c 18 cm. In trigonometry, the law of sines, sine law, sine formula, or sine rule is an equation relating the. In the video solving for an angle with the law of sines, sal solves for only one of the two possible solutions. Sas side, angle, side asa angle, side, angle aas angle, angle, side sss side, side, side hl hypotenuse leg for right triangles. Adjust the slider for a until it is just long enough to form one triangle. With the following two math lib activities, students will practice using the law of sines and law of cosines to find missing side and angle measures in triangles. May 02, 2016 learn how to solve a triangle using the law of sines when it is the ambiguous ssa case in this free math video tutorial by marios math tutoring. The sides of a triangle are to one another in the same ratio as the sines of their.
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