Law of Sines & Cosines Worksheets for 10th Grade
Apply the law of sines and law of cosines to non-right triangles.
About Law of Sines & Cosines
Right Triangle Trigonometry introduces the three fundamental ratios — sine, cosine, and tangent — that connect angles to side lengths in right triangles. Students learn to apply these ratios to find missing sides and angles, solve real-world problems involving angles of elevation and depression, and extend trigonometry to non-right triangles using the Law of Sines and Law of Cosines. This unit opens the door to one of the most powerful areas of mathematics.
The Law of Sines and Law of Cosines extend trigonometry beyond right triangles to all triangles, dramatically expanding what can be calculated. These tools are used in navigation, structural engineering, and game physics, and they connect to the deeper theory of trigonometric identities and the geometry of the unit circle.
What Your Child Will Learn
- Apply the Law of Sines to solve oblique triangles
- Apply the Law of Cosines to find missing sides or angles in any triangle
- Determine which law to apply given AAS, ASA, SSA, SAS, or SSS information
- Identify the ambiguous SSA case and determine how many triangles are possible
- Calculate the area of any triangle using the formula involving two sides and an angle
Worksheets by Difficulty
Start with Easy worksheets to build confidence, then progress to Medium and Hard as your student masters each level.
Understanding the Difficulty Levels
Worksheets 1-3 are Easy level — designed to build confidence with simpler numbers and straightforward problem types. Great for introducing the concept or reviewing basics.
Worksheets 4-7 are Medium level — offering a moderate challenge with larger numbers, varied question types, and more problems per worksheet.
Worksheets 8-10 are Hard level — featuring the most challenging problems including multi-step questions, missing values, and real-world applications.
Tips for Parents & Teachers
SOH-CAH-TOA is the most important mnemonic in high school mathematics — make sure your student has it absolutely cold before moving on.
The most common error in trigonometry is using the wrong ratio. Encourage your student to always label the sides of the triangle (opposite, adjacent, hypotenuse) relative to the angle in question before choosing a ratio.
Inverse trig functions (arcsin, arccos, arctan) are used to find angles. Make sure your student understands these are the "undo" buttons for the trig functions.
For Law of Sines vs. Law of Cosines: Law of Sines is used when you have an angle-side pair. Law of Cosines is used when you have three sides or two sides and the included angle.
Frequently Asked Questions
What will my child learn from law of sines & cosines worksheets?
These 10th Grade law of sines & cosines worksheets help students practice trigonometry, law of sines, law of cosines. Each worksheet provides structured practice with clear instructions and varied problem types.
How often should my 10th Grade student practice law of sines & cosines?
Consistent practice works best. We recommend 10-15 minutes of focused practice 3-4 times per week. Start with Easy worksheets and progress to Medium and Hard as your student builds confidence.
Are these law of sines & cosines worksheets free to print?
Yes, all 10th Grade law of sines & cosines worksheets on K12Worksheets are completely free. You can download and print as many as you need for home or classroom use — no signup required. Each worksheet includes a printable answer key on a separate page.
How do I know which law of sines & cosines worksheet to start with?
Begin with the Easy worksheets (Worksheets 1–3) to assess your student's current skill level. If they complete these confidently, move to Medium (Worksheets 4–7). Reserve Hard worksheets (Worksheets 8–10) for students who have mastered the basics. If your student struggles with Easy worksheets, revisit prerequisite topics first.