Ambiguous Case: Error Analysis & Misconceptions
Mathematics
Year 9
11 questions
~22 mins
1 views0 downloads
About This Worksheet
A worksheet exploring the Ambiguous Case of the Sine Rule, focusing on common errors, misconceptions, and problem-solving strategies for Year 9 students.
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Ambiguous Case: Error Analysis & Misconceptions
Subject: MathematicsGrade: Year 9
Name:
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Untitled Worksheet
Grade Year 9
A
Fluency & Practice
Answer the following questions to develop procedural mastery. Show your working in the grid spaces provided.
1.
Given a triangle with sides a=7 cm, b=10 cm, and angle A = 40°, use the sine rule to find angle B. Show your calculations.
[3 marks]2.
In a triangle, sides are a=8 cm, b=12 cm, and angle A=30°. Determine whether the sine rule will give one solution, two solutions, or no solution for angle B.
[2 marks]3.
Calculate the possible values of angle B when given sides a=5 cm, b=9 cm, and angle A=60°, considering the ambiguous case.
[3 marks]4.
If the sine rule produces two possible angles for B in a triangle with given sides, explain how you determine which is the correct angle in a real-world context.
[3 marks]B
Problem Solving & Reasoning
Work through these multi-step problems, providing full explanations for your reasoning.
1.
A ship is sailing towards a lighthouse. The angles of elevation from two points 150 m apart are 35° and 50°. Assuming the lighthouse is directly behind the second point, find the height of the lighthouse. Consider the ambiguous case when applying the sine rule.
[4 marks]2.
Given sides a=6 cm, b=10 cm, and an unknown angle A, determine all possible angles B if the triangle is ambiguous. Explain how the sine rule leads to multiple solutions and which is valid based on the context.
[3 marks]C
Real-world Applications
Solve these word problems by applying your understanding of the ambiguous case in the sine rule.
1.
A drone pilot needs to determine the angle at which to tilt the drone to reach a target located 150 meters away, given certain side measurements. If two possible angles satisfy the sine rule ambiguity, explain how the pilot might decide which angle is appropriate. Provide calculations if necessary.
[4 marks]D
Challenge & Extension
Attempt these more challenging problems, which involve critical thinking and extension of the ambiguous case concept.
1.
Construct a triangle with sides a=9 cm, b=14 cm, and an angle A=55°. Using the sine rule, determine all possible angles for B and discuss the conditions under which the ambiguous case occurs.
[4 marks]2.
Consider a scenario where two triangles satisfy the same side lengths and one angle, but differ in the other angles due to the ambiguous case. Describe how you would verify which triangle is valid in a real-world setting.
[3 marks]E
Mixed Review & Error Analysis
Review common errors in applying the sine rule to ambiguous cases and answer the questions below.
1.
A student applies the sine rule to find angle B and concludes there is only one possible solution. Identify a common mistake that leads to this misconception and explain how to correctly determine the number of solutions.
[3 marks]2.
Given a set of side lengths and angles, a student finds two possible angles for B but only reports one. Explain why both solutions are valid in the ambiguous case and how to present both in your answer.
[2 marks]Quick Actions
What is Remix?
Create a new worksheet based on this one. Change the grade level, topic, number of questions, or difficulty - then generate a fresh version.
- • Change grade level (Grade 6 → Grade 7)
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- • Add more questions (10 → 15)
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Details
- Created
- 1/1/2026
- Updated
- 1/1/2026
- Type
- worksheet