Free Printable WorksheetMathGeometryMath CurriculumG-SRT.D.9-11 (+)

GEO.100 Law of Cosines Worksheet

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Worksheet Overview & Skills Covered

Core academic competencies and curriculum alignment

This Geometry Math worksheet provides structured practice on GEO.100 Law of Cosines. Students are guided through targeted exercises that build foundational understanding, computational accuracy, and critical thinking skills.

GEO.100 Law of Cosines - Primary standard selected for prompt fields in this prompt cell: CCSS G-SRT.D.9-11 (+). Skill statement in this prompt cell: Select the correct Law of Cosines equation and determine an unknown side length or angle measure in a triangle. Associated standards listed with this skill in the curriculum source: CCSS G-SRT.D.9-11 (+); NY HS Plus; MA G-SRT.D (+). Use this prompt-provided wording as the supporting standard description for this workflow.

Whether you are an educator preparing classroom handouts, a tutor reinforcing weekly topics, or a parent supporting homeschool learning, this printable resource gives students the deliberate practice required to achieve subject fluency and master state standards.

Grade

Geometry

Subject

Math

Domain

Math Curriculum

Formats

PDF & DOCX

Sample Practice Problems

Preview the types of problems and questions covered in this worksheet

Below are sample questions representative of the exercises included on this worksheet and related GEO.100 Law of Cosines skill assessments:

Problem 1Difficulty: Mastery
A triangle has sides 27, 35, and 44. Which angle measure is closest to the angle opposite the side of length 44?
Aabout 89 degrees
Babout 91 degrees
Cabout 53 degrees
Dabout 38 degrees
Solution & Explanation:Use the Law of Cosines with 44 as the opposite side: cos(theta) = (272 + 352 - 442)/(2(27)(35)) = 0.0095. The inverse cosine gives theta about 89 degrees.
Problem 2Difficulty: Mastery
Two ground anchors are 28 feet apart. Wires from the top of a pole connect to the anchors and have lengths 32 feet and 45 feet. What is the angle between the two wires at the pole, to the nearest degree?
Aabout 142 degrees
Babout 97 degrees
Cabout 45 degrees
Dabout 38 degrees
Solution & Explanation:The pole angle is between the two wire lengths 32 and 45, and the side opposite that angle is the 28-foot anchor distance. cos(theta) = (322 + 452 - 282)/(2(32)(45)) = 0.7865. Therefore theta is about 38 degrees.
Problem 3Difficulty: Mastery
Which statement about the Law of Cosines is accurate?
AIt can be used only in right triangles.
BIt can be used in right and non-right triangles.
CIt can be used only when all three angles are known.
DIt never reduces to the Pythagorean theorem.
Solution & Explanation:The Law of Cosines works in right and non-right triangles. When C = 90 degrees, cos(90 degrees) = 0, so the formula becomes the Pythagorean theorem.

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Frequently Asked Questions

Common questions about printing, using, and solving this worksheet

QHow do I download and print this GEO.100 Law of Cosines worksheet?

Click either the "Download PDF" or "Download DOCX" button at the top of the page. You can print the PDF directly from your browser or edit the DOCX file in Microsoft Word or Google Docs to tailor the questions to your students.

QIs this GEO.100 Law of Cosines worksheet free for teachers and homeschoolers?

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QCan students practice GEO.100 Law of Cosines online with instant feedback?

Yes! In addition to this printable worksheet, students can practice GEO.100 Law of Cosines interactively on our platform with automated grading, instant score tracking, and detailed step-by-step solutions.

QWhat grade level and standards does this worksheet align with?

This worksheet is designed specifically for Geometry Math students. It aligns with educational standard G-SRT.D.9-11 (+) (Primary standard selected for prompt fields in this prompt cell: CCSS G-SRT.D.9-11 (+). Skill statement in this prompt cell: Select the correct Law of Cosines equation and determine an unknown side length or angle measure in a triangle. Associated standards listed with this skill in the curriculum source: CCSS G-SRT.D.9-11 (+); NY HS Plus; MA G-SRT.D (+). Use this prompt-provided wording as the supporting standard description for this workflow.).

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